Check out adventurecycling.org. They've got the best TransAm routes and maps, and a couple other routes that are fully mapped out, with directions, services, etc. all listed. There's a couple of books in their bookstore that are good reads, but for a route, go with the maps. OTOH, if you're looking for how to do it, go read the articles in their HOWTO section.
Have you been to Adventure Cycling? They have maps for 3 different trans-continental routes.
Im hoping to not spend $165 for the route information. For my last tour i did the west coast down to LA via a book called Cycling the Pacific Cost. It had maps, places to stay, cool things to do and see. All for $4.50 used from Amazon. Is there anything like that book for this kind of tour?