Albuquerque. I would have happily stayed there for weeks. I loved the strange combination of adobe, Art Deco and modern buildings, and the clean, high air (so dry that, as one elderly man told me, "Old folks don't die in Albuquerque, they just dry up and blow away"). I loved the mighty Rio Grande, sunk into its 1,500m plateau and fringed with cottonwoods and red willows. I loved the fact that when waitresses asked: "Red or green chilli on that food, ma'am?" people would answer: "Christmas," which means both.

Yup, I loved this city. But the road beckoned. My cousin Libby and I were going on a road trip, driving north from Albuquerque (roughly in the centre of New Mexico) and looping around what they call the North-West Corner. We would be like Thelma and Louise, but without the handguns - and, preferably, the cliff.

And the bars, for that matter. As we slid north on the Interstate 25, between the Rio Grande and the Sandia Mountain range, we were in pueblo country. There are 19 American Indian villages (pueblos) in this part of the state that have retained their independence for centuries, and many of them are dry.

Acoma Pueblo is a towering plug of rock standing almost 120m above the valley floor, with a village and church on top. It used to be completely impregnable - its adobe apartment-style housing and kivas (ceremonial circles) reached only by a secret, twisting stairway through the rock. Then Hollywood arrived and a road was built up to the top for a John Wayne movie. Even now, no-one goes up there without permission: tourism is controlled by the tribe, and its members guide visitors and sell pottery. The novelist Willa Cather described this mesa valley as a collection of half-finished Gothic cathedrals, surrounded by building materials. It was so surreal - so New Mexican.

We didn't have time to stop at all the pueblos. That's the trouble with a road trip: the road. You have to keep driving, keep looking forward to the next place. So we drove up - literally, it's 600m higher - to Santa Fe, the state capital. It's larger and sleeker than Albuquerque's Old Town, and is awash with adobe, the sundried mud bricks that give the buildings their sensuous, curving walls. They look as though they have been dusted with demerara sugar, and you feel as if you're walking through the world's first hobbit city. In town, everything - laundrettes, schools, garages - seemed to be outdated, including a divorce attorney's office. It must be like having your separation handled by Bilbo Baggins.

But Santa Fe is sophisticated. In the rolling hills of juniper and sagebrush around the city, the low adobe mansions of the rich hunkered down, dissolving into the desert landscape. The owners have a taste for art - Hispanic, American Indian, contemporary - and decorate their interiors with beautiful artefacts, from Navajo rugs and pueblo pottery to the crude religious figures carved by early Spanish settlers. So the plaza is heaving with shops, and Canyon Road is a gauntlet of expensive galleries. There are also a dozen museums. You need days to do them justice, but we only had one, so we raced from Georgia O'Keefe's eerie flowers, to the Native American Art Museum.

The further you get from the centre of Santa Fe, the more relaxed and hippyish the houses become. Gardens, instead of being discreetly walled, sprout bits of cars and half-finished DIY projects. I felt more relaxed, too; I found the city somehow oppressive. Anyway, I was excited: we were heading for Taos - which Libby had visited the year before and talked about ever since - via Bandelier National Park.

Bandelier is small (for an American park) but spectacular, formed from a huge volcanic explosion in the prehistoric past. The pink cliffs are honeycombed with American-Indian caves, including a kiva that you can descend into (most are sacred and off-limits to tourists). Gigantic ponderosa pines soar towards the blue sky, and little walkways and ladders go up to the caves.

From Bandelier we took the back road to Taos - a place that does things to people. Somehow, the town fuses all the elements of northern New Mexico: art and artists, intense colour, the abstract shapes of adobe, Indian, Hispanic and Anglo cultures, natural beauty and a very particular sort of hippy chic.

As we drove to our B&B, Libby kept exclaiming about things she remembered from last time: a shop, a café, a bookshop. Our two days there were punctuated with the frenzied clicking of her camera shutter. It's that sort of place. And, like Albuquerque, it's dominated by a mountain that is sacred to the pueblo Indians. Elton, from San Antonio, Texas, told us about his conversion while serving us breakfast in the B&B: "It was a couple of years ago now. I was standing here cutting fruit and staring at the mountain," he said. "Dennis [the owner] said: 'If the mountain wants you to stay, it will tell you to stay'. And I said: 'You know what? I think it already did.'"

The B&B once belonged to Mabel Dodge Luhan, one of those rich women who scandalised polite society by marrying a man from the pueblo. Libby and I were staying in the Cowboy Room, and when we came back in the afternoon, the gold Taos light caught the iron cowboy hanging outside and printed its reflection on the orange-brown wall.

Taos is a collection of impressions for me now: standing by the brazier at Orlando's restaurant, the firelight flashing on the silver and turquoise jewellery worn by the men; a day at the pueblo and a tour of the little chocolate-brown church and honey-coloured houses; DH Lawrence's peaceful ranch with a note in the visitors' book in childish writing saying "What a stupid place to live!"; the sky exploding with hard, crystalline light each morning that turned gradually into a wash of dazzling, chemical blue.

Most things in New Mexico are above 1,500m, which gives everything an extraordinary clarity. At the same time, the altitude dries your eyes out (so you blink a lot), and dehydrates you, so you can drink pints of water and still feel parched. Apparently this wears off after a month or so, when the body acclimatises. For visitors, it is a constant reminder that, although things look normal, everything is extreme.

The mad, colourful food, for example: the huge puffy corn kernels called posole (Anglos call it hominy) with purple onion, scarlet tomatoes and white pork; the golden pillows of wheat flour sopapillos, eaten with honey to cut the chilli burn; Indian fry bread, pueblo burgers, beef enchiladas - all seared with Christmas chillis. Or the adobe churches, re-plastered by their communities every few years, with solid bodies and buttresses, and flat bell towers, which throw insanely black shadows onto the dusty ground, so they look like lino cuts come to life.

It's odd. And as we drove out of town, west over the Rio Grande gorge (now so deep and wide that even the bridge across it is terrifying), things were about to get odder. First we saw strange mounds on the ground which, on closer inspection, turned out to be a community of Earthships - private homes built entirely of recycled materials - including a showhome. It was vast and airy, full of plants and light. A blonde woman with dazzling blue eyes gave me a video to watch and a guided tour.

Outside, the sun beat down and there was no shade for miles. Libby had swapped adobes for clouds as photographic subjects. "Look at that!" she said, "It looks like a spaceship!" It did, too. I kept an uneasy eye on it as we barrelled along the road, looking out for the Pink House, an old schoolhouse that Elton had told us to stop at: "Oh you'll love Ken! Tell him Elton sent you. He'll go [gravelly voice] 'Oh yeah? Go on in'." He told us we couldn't miss it, and he was damn right: it stood out like a giant piece of bubblegum on the tawny plateau. And there was Ken, with a pack of dogs. "Hi!" we said, "Elton sent us!" "Oh yeah?" he said in a voice so deep it made the sagebrush vibrate. "Go on in".

We did, wandering through an eccentric collection of Mexican textiles, Indian masks and a full-size wooden canoe. "You from England?" he said. "The only people who wove herringbone patterns on a back-strap loom were the English and Oaxacans." As we pulled away, we craned our necks to see if the spaceship had got any closer. It hadn't. In fact, it had turned into a beautiful sweep of cloud, like one side of a feather.

I now think the Pink House is the official border between heightened, surreal northern New Mexico, and the rest of America. It was such a stunning drive - along Route 64 from Tres Piedras to Tierra Amarilla, through a sloping valley with a stream at the bottom and grassy meadows - that Libby forgot clouds and moved on to aspens. We stopped time and time again to get the perfect shot of the perfect, parchment-white trunk with the perfect, shivering canopy of leaves.

The colour scheme had changed from hot oranges and reds to cool greens and silvers. We were in ranch country: the Red Rabbit Ranch, the Big Wheel Ranch, and Valley Feed and Mercantile. Then, there ahead of us, were the Rockies: white-capped and forbidding blue, a distant, impenetrable wall.

We stopped in Chama, an old railroad town with a narrow-gauge railway that runs up into the hills. House colours were muted - purples, greys, duck-egg blues - because of the soot off the railroad. In the railyard, giant locomotives stood about, twice my height. They weren't going anywhere. Dogs slumped between the tracks, and a sign said "You are in Bear Country. If attacked, FIGHT AGGRESSIVELY." There was a cracking B&B - the Gandy Dancer (named after the railway workers who carried tools made by a company called Gandy) - and a vibrant bar.

But then we found ourselves running out of time. Libby's flight home left before mine, and suddenly we were racing to get to Farmington, a ranching town on a flat valley floor which discovered gas and oil back in the 1950s, and can afford a good little museum. We zoomed across the desert, trailing a cloud of dust, until we remembered that spotter planes monitor traffic speed.

I put Libby on the plane and, to counter the sense of anti-climax, drove back up into canyon country, to a spa called Ojo Caliente or "Hot Eye". It has hot mineral pools once used by pueblo Indians as a wintering place.

I sat in the Arsenic Pool, sticking my toes out of the steaming water and watching in amazement as a woman in a one-piece flirted intently with a man bobbing nervously up and down on his toes. Speed-dating in arsenic. New Mexico really is something else.

TRAVEL BRIEF

Getting there

Trailfinders (0845 050 5855, www.trailfinders.com) has flights with United Airlines from Heathrow from £413. Regional add-ons from £53. American Airlines (0845 778 9789, www. aa.com) flies to Albuquerque via Dallas from Gatwick from £515. Add-ons from £60.

Where to stay

The Mabel Dodge Luhan House (00 1 800 846 2235) in Taos has doubles from £52. Ojo Caliente Mineral Springs (00 1 505 583 2233) has doubles from £68. Use of the mineral pools and spa treatments starts at £9. The Gandy Dancer (00 1 800 424 6702) in Chama has doubles from £55. La Posada de Albuquerque (00 1 800 777 5732) in Albuquerque has doubles from £50. The Inn of the Anasazi (00 1 800 688 8100) in Santa Fe has doubles from £110.

Getting around

Trailfinders can arrange one week's car hire from £133, with a free upgrade to an SUV when you book a full-size car (from £174 per week). Or try Avis (0870 907 7300) or Hertz (0870 848 4848).

Tour operators

North American Highways (01902 851138) has a similar route to the one featured from £1,498pp (based on two sharing), with flights from Gatwick to Albuquerque, accommodation for 13 nights, car hire and a half-day trip on the Cumbres & Toltec Scenic Railroad.

America As You Like It (020 8742 8299) also has a similar package with flights from Gatwick, accommodation for 10 nights, and car hire, from £785pp (based on two sharing). Or try North American Holidays (01892 619000) or American & Worldwide Travel (01892 511894).

Where to eat

Albuquerque: 66 Diner (00 1 505 247 1421) on 1405 Central for American classics. Mains from £4. Casa de Ruiz (00 1 505 247 8522) on Church Street for typical New Mexican food. Mains from £5.

Taos: Orlando's New Mexican Café (00 1 505 751 1450) serves great Mexican food and is always packed, so arrive early. Mains from £4.

Farmington: Three Rivers Brewhouse & Eatery (00 1 505 324 2187) at 101 E Main Street is set in the old drugstore and serves good beer. Mains from £5.

Further reading

Triple A's Indian Country Guide Map (£2.60); Southwest USA (Lonely Planet, £14.99); Eyewitness Travel Guide: Southwest USA & Las Vegas (Dorling Kindersley, £14.99).

Tourist information

Contact the New Mexico Tourism Office (01489 557534) for maps, a free Vacation Guide and useful website information. New Mexican Pueblos (00 1 505 843 7270) has information on which ones to visit.

The Cumbres & Toltec Scenic Railroad (00 1 505 756 2694) runs from Chama and Antonito between May 28 and October 16 2005 and costs £36 for adults and £19.45 for children (return trip by bus). The best time to go is in spring and autumn - summer temperatures can reach 37ºC and snows hit the north in winter.