Been there, done that, doing it again someday

Route 66 Backroads:

Your Guide to Scenic Side Trips & Adventures from the Mother Road

by Jim Hinckley

Not a guide to Route 66, but a guide to the side trips off Route 66 where you get to see the good stuff.  It's an interesting way to plan a book, and I could see it being indispensable.  If, for example, you were a person who decided to travel the entire route in a leisurely series of one to two week travels, you'd want to have this book along to goad you into getting off the interstate, the feeders, and the few stretches of the original road. You'd want to see museums, botanical gardens, lakes and volcano craters.

And it's gorgeous, too. Don't try to sit down with this and read it through, but definitely pick it up whenever you're planning a trip in those areas.  My list of places I must go somewhere has doubled overnight.