One of the local bike club members was getting ready to ride the trail this week.
He had this book: C&O Canal and Great Allegheny Passage Trailbook. It included a really nice map (weatherproof!) in the style of the Blue Ridge Parkway maps. $10.00
Includes Linking Up! planning guide; weatherproof, full-color map is folded into the back pocket; contains 248 pages of trail information; plus maps and information on 15 key trail towns. It's loaded with pictures of what you will see as you experience what the National Geographic Adventure calls an American Classic.