Rambling Man (Bruce) let me borrow a coffee table book he has called "The most scenic drives in America".
It has a listing by region of 120 road trips, hard cover, 400 pages. It's very easy to use and could come in handy for planning trips. I found several places on e-bay to buy it. Here's a link for the seller I bought from.
http://cgi.ebay.com/The-Most-Scenic-Drives-in-America-120-Spectacular-Roa_W0QQitemZ150209042189QQihZ005QQcategoryZ377QQrdZ1QQssPageNameZWD1VQQ_trksidZp1638.m118.l1247QQcmdZViewItem
In looking at the Readers Digest web site there are several other books offered there along the same theme that look very good. Their prices are a bit higher than e-bay though.