Wells' book is worth having. It's great in conjunction with the Atlas or Gazetteer. And so are:

• The Four Wheel Drive Trails of Arizona Vol 1,
• 4 Wheel Drive & Back Roads of Yavapai County, AZ,
• 4 Wheel Drive Roads of Mohave County, AZ,
• The Black River A Fishing and Camping Guide,
• Backcountry Adventures, Arizona

The trail books will give you trail-specific details, while the Atlas/Gazetteer will give you the larger context.