Whitmore Canyon Overlook is 1,000 feet above the Colorado River in the Grand Canyon. The switchbacks descend 1,500 feet across an ancient lava flow to the viewpoint. NPS. These road descriptions refer to the main visitor routes south of the Mount Trumbull schoolhouse. Roads are listed in numerical order. Use this guide with the BLM Arizona Strip Visitor Map. Most roads in this area should be explored with a high clearance four wheel drive vehicle with all-terrain tires in good condition at a minimum. However, some roads are only suitable for UTVs or specially modified short wheelbase 4x4s.