You're just getting your breath back after rejoining the I-40 at Correo when yet another treat beckons at Exit 117. The Mesita loop is wonderful. The old road sweeps and curves through a landscape of mesas and cottonwoods. It's as pretty as a picture and I bet I'm not the first traveller to go back and do part of it again for the sheer joy of it. To cap off a brilliant hour, a mighty Southern Pacific 4-header, sirens wailing, thundered majestically through the very gap I'd chosen for a key-note photograph. Stirring stuff.

Each of the succeeding villages holds treasure for the true Roadie. As Tom Snyder has observed, this section is "like driving into an old View-Master scene." After enjoying Laguna, Budville and McCartys, it was a little disappointing to find Grants cut off by a barrage of signs reading "Road Closed - Bridge Out". I thought I'd strayed onto the set of "The Dukes of Hazard" and half expected an orange Dodge coupé to come flying through, smashing the barriers to match-wood. It didn't happen, so I proceeded tamely on my way to Thoreau (elevation 7200 feet).

Up to this point on your journey, all the rivers you've crossed have flowed south or east towards the Gulf of Mexico. At Exit 47, you can photograph your car at the Continental Divide after passing which all of the rivers will be flowing westwards to the Pacific. Here there used to be a range of tourist-trapping attractions and some of the guide books still tell you to cruise in and wander amongst the remains. However, the signs I saw left little doubt as to the violent end awaiting any trespasser amongst these sad monuments to unfettered free enterprise.

El Rancho Hotel

And so to Gallup, the "Gateway to Indian Country". You will already have passed by - or perhaps even stopped at - various Indian pottery, rug and jewellery trading posts. From Gallup onwards through Arizona, they're everywhere. As in life, there's good and bad, so be careful when negotiating for that genuine hand-made artefact. Take local advice about the more reputable outlets. Gallup was originally just another railroad siding, founded in 1881 when the Santa Fe Railroad came through. In the 'twenties, however, the movies came to town. The genre of the Western was taking off in a big way, and where were most Westerns shot? In the deserts of New Mexico, of course. Brilliant light, fantastic scenery, fine weather most of the year, cheap Indian and Mexican "extras" - perfect. But where could the stars stay out here in the wilds? Voilà, the El Rancho Hotel. "The charm of yesterday and the convenience of tomorrow." The dark, Spanish-inspired lobby is festooned with hundreds of signed photographs of everyone you've ever heard of who made a movie between the 1920s and the 1980s. Each room is named in honour of a star who stayed here. I'm afraid I got room 305, the Sydney Greenstreet room. Who he? The El Rancho is a rare find indeed - friendly, clean, comfortable, different and authentic. I can also vouch for the excellence of the bar and restaurant. Whoever Sydney Greenstreet was, he had a great view over the railway line from the veranda outside his room. Awesome trains of more than 100 giant wagons rumble by just across the street. With as many as four locos pulling and two pushing, they have the braking performance of the QE2 and so must sound a continuous warning of bells and whistles as they bisect the town, the lead locomotive having left the eastern suburbs while the tail is still in the western approaches.

You'll know you're in Arizona when the Teepee Trading Post looms into sight, its 60-foot concrete wigwam an irresistible draw for lovers of kitsch. By the time you get to Indian City a few miles up the track, you begin to wonder if there's anything more to Arizona than trading posts. There sure is! And from Exit 311 on I-40 we'll take you slightly off the main 66 through-route for what I found to be one of the unexpected highlights of the journey. Back on a miserable, wet October Sunday, I pulled in to visit the Petrified Forest and Painted Desert National Park Visitors' Centre, intending to collect some information and press on. But once I saw what I might be missing, I paid my $10 entrance and embarked on the full run through the park. Almost at once, I came to the first of a series of spectacular view-points over the many-hued sands and rocks of the Painted Desert. Even under a leaden sky in the pouring rain, this was a tremendous show. Crossing over to the south of I-40/US66, the Petrified Forest begins to reveal itself. This isn't just some isolated prehistoric tree stump sticking out of the sand; there are thousands of substantial remains of this mighty jungle, many in picturesque settings among the desert's valleys and dry watercourses. It is amazing that there is so much left when you see how these precious reminders of remote time have been mined for trinkets and souvenirs over the centuries of human occupation. The National Park road leads you right through to State Highway 180 on which you turn north to rejoin 66 at Holbrook. You lose little and gain a huge bonus by following this minor deviation form the Mother Road, and it's only 25 miles back from Holbrook to Exit 311 if you're a perfectionist and want to make sure you've driven every inch of 66!