John Hutchins from Pacific on 2/20/2020 7:59:44 AM:
I rode both last spring. The websites Ray listed are the best. I'd also recommend the trail book https://gaptrailstore.org/collections/featured-products/products/trailguide-15th-edition
The book doesn't do much more for you than the web info, but the map is worth the price. The GAP is a fabulous ride. The C & O is fascinating but rough, mud, pot holes, rocks, roots etc. From the GAP you can connect to the Montour and Panhandle trails and another that follows the Ohio River all the way to Wheeling W.V.