If you dream of road tripping across the American Southwest, forget about Route 66. The Mother Road is okay, but the best of the mountains and desert are found on trails that would rip out the oil pan from under a rental.For a go-where-you-please exploration, you want a Jeep. Tough, American, iconic. I’m reminded of this as I rumble up the path to the house where I grew up, a dirt track so rocky you need a 4X4 to reach it.My hometown of Kirtland, New Mexico, has a single stoplight to occasion a pause through the high desert on the way to the Four Corners monument, where New Mexico, Utah, Arizona and Colorado meet. Out here, off-roading is just called driving.Luckily, my prodigal ride isn’t an ordinary Jeep Wrangler. It’s an $81,284 mega-Jeep from Missoula, Montana-based American Expedition Vehicles, which converts new and old Jeeps into extreme off-road bruisers. Around since 1997, it takes about 250 custom orders a year.My test specimen started life as $36,000 four-door, 2011- model-year Rubicon. The extra $45,000 includes a custom suspension, lift kit, winch and specially outfitted drivetrain. It sits loftily off the ground upon 35-inch BF Goodrich mud tires so large they could fit a tractor. A running start helps to vault into the aerie-cum-cockpit.The 6.4-liter Hemi V-8 with 465 horsepower and 465 pound- feet of torque is an option not available in the regular Chrysler product. The privilege costs a whopping $28,000, but makes other Jeep owners coo in appreciation.I picked the AEV up in Albuquerque, where the odometer rolled over to 15,000 miles as I ambled northwest toward Kirtland, a 180-mile drive. I’ve found that only Mongolia’s Gobi desert compares to the elemental blue of New Mexico’s sky. I took off the roof panels to better appreciate the clean, sweet light.Despite the high center of gravity and knobby tires, the AEV corners in a flat manner and rides comfortably. The V-8’s extra power is welcome on high-altitude mountain passes, but the observed gas mileage of 13 highway, 10.5 off-road, is not. I’d already burned $200 worth of 91 octane.My 65-year-old dad, John, and I drove into the desert mesas where our family once ran cattle. Winding up arroyos, or dry washes, we headed toward a distant rock outcropping where my granddad, also John, chiseled his name while astride a horse sometime in the 1940s. Prairie dogs chirped at us. The AEV easily crunched over dirt escarpments and rock gardens.The next morning we threw in a jack, sleeping bags and shovel, and struck north to Colorado’s Uncompahgre National Forest and the San Juan mountains. Through the city of Durango, no longer so sleepy, past fields of grazing elk, and to Silverton.Dad and I have done this type of trip before, and we were soon on a squiggling, perilously narrow road over Engineer Pass, well above the tree line, where oxygen is scant and the wind bites. You have to train your eyes to accept the vast distances, the brutal beauty.This is Jeep country and we passed a dozen kindred vehicles. The difference is most of those owners spend their free weekends bolting on custom parts. The AEV is a one-stop- shopping affair, for the kind of driver who prizes free time over cash.Unlike, say, a new Land Rover, Jeeps remain fairly low- tech. There are no hill-descent functions or electronic terrain selections for mud and ruts. Your most important tools are high- and low-range 4X4 and good judgment.“This rig can go anywhere,” my father said appreciatively as we rolled into the village of Ouray, which still has dirt side streets. “I love it.” Of course he wasn’t paying for gas. My tab so far: $306.The next morning, on Imogene Pass from Ouray to Telluride, we were rebuffed by a thick accumulation of new snow at the summit. Reluctantly turning around, we instead made for a former mine, called Mountain Top, which is aptly named. The road was no wider than our vehicle, with blind corners and no room for mistakes.Creeping along, I hoped for no oncoming off-roaders. Somebody would have to reverse, which could prove to be lethally unfortunate.Reaching the lonely mine without incident, we explored a decrepit bunkhouse with buckled wood floors and coiled, rusted bedsprings. Rock walls rose on all sides around us, sharp spires slicing into a pale sky.The site was both beautiful and terrible in its remoteness. There would be thick snow here, too, very soon. I couldn’t imagine being socked in for the winter like those former miners.Two days later, back in Albuquerque, the AEV’s odometer rolled to 16,000 as I put it into park. One thousand glorious miles and $392 of gas charges. Worth every cent.