Who makes the best ones, and where can I buy one? Ideally, it would cover camping sites, safe routes (least vehicle traffic), and of course food stops. I'm primarily interested in the U.S. of A., but if they make others, other folks might find that useful. Thanks.

If they go where you want to go you might look at https://www.adventurecycling.org/routes/index.cfm you might also write states DOT for bike maps

Ditto the above. I'll add that electronic apps like Google Maps can be a powerful tool, but you really need some local knowledge to make them work. If I google a route in my mountainous neighborhood, it takes me over some mapped mountain bike trails I don't have the skills or equipment for.

the best:

https://shop.delorme.com/OA_HTML/DEL...?section=10096

Go to your local automobile association, to your local tourist information place, to your local bookstore, newsagency, and sporting goods stores ... see what you can find.

I believe that most if not all of the rail-to-trails have guidebooks. Look at their websites.
Personally I'm looking forward to moving up to GPS.

They do, but they vary in quality from Google Maps screenshots to amazing, plus just the pain of figuring out each individual trail and going and hunting them down.

Can't speak to all states, but I know the Michigan DOT produces bicycle specific maps, free for download or you can order them on the website: MDOT - MDOT Road and Trail Bicycling Maps. Also, you may try the local state bicycling association. Again, can't speak to all states, but ours provides some good resources: Michigan Bicycle Routes and Maps

Falk, NL, made one especially for bike route highlights.. slit so you only open, like fold out pages, a portion of a big panel .

Ordinance Survey.. British Isles. shows where historic sites are ..



Oregon DOT has a state bike route map and 1 of the Coast Route ..

Most state's publish bicycle maps. Check with each state's department of transportation. They vary in the amount of information they have.