Potash Road The Colorado River along Potash Road. The Potash Road follows the river for a long stretch, in which the road is fairly level and easily driven with a 2-wheel drive vehicle. Once the road leaves the river and begins climbing you need 4-wheel drive to maneuver the rocks and ruts on what is now a gnarly dirt road trail. it is an exciting and amazing ride. Potash Road ends when it becomes the Shafer Trail in Canyonlands National Park.