By the time you make it to the Colorado River, the vegetation has all but disappeared, and you're riding through a low-desert environment.
A big piece of the epicness puzzle is the diversity of this route. The Whole Enchilada passes through almost every climate zone imaginable. The top of Burro Pass, the route's high point, tops out just above treeline in alpine tundra. The singletrack quickly drops back into the trees, swooping through a pine forest. Lower down, the pines switch to aspens, and then low scrub oaks. The vegetation switches to the high desert variety, with short pinion trees breaking up the landscape. By the time you make it to the Colorado River, the vegetation has all but disappeared, and you're riding through a low-desert environment.