I don't know about maps or other sources, but Harvey Botzman, owner of CycloTours and author of 'Round Lake Erie is a member of my club. I've ridden with him many times. He donates books for club prizes and I won 'Round Lake Erie, the 2004 2nd edition.
The book is incredibly detailed. For each section, (sometimes as little as a couple of miles) there is a map, cue-sheet (showing both clockwise and counterclockwise mileage) and something about that part of the ride. Attractions, lodging and comments like, "Wow! What an intersection!" come to mind. It's also filled with useful tips, like how and where to cross the border with your bike. Often, there are route alternatives given.
Harvey has his own ideas about typographical conventions, and there are sections I wish had a little more white-space, although I understand the need to keep it small and light. Otherwise, it seems to be a perfectly serviceable companion for the trip.