I'm surprised no one has mentioned the www.militarycampgrounds.us
website. It's run by a civilian (who does it for free) and who has been doing it for years. It's free, although you can purchase a download that you can use on your computer when you don't have Internet access.
Here you will find more complete information about military cg than I've found at any other site. There are also reviews of the campgrounds from people who have stayed there. You'll also find information on cost, restrictions (if any) and directions that will tell you which gate you have to use.
A few of the CG are off base in recreation areas but most give you the security of a "gated community. :) We have stayed in these CG from Alaska to Key West and Boston to Seal Beach, CA and found them to be a great deal. Some are nicer than others but for the most part the benefits outweigh the negatives. We'll be staying at Joint Base Andrews and Fort Meade during our visit to DC in a couple of weeks and you can't beat the price and location.
Hope this helps.
