If you want to explore the entire cemetery, which is enormous and hilly, in a short amount of time, there is an interpretative tour that departs continuously from the Welcome Center between 8:30 a.m. and 6:00 p.m., April through September, and between 8:30 a.m. and 4:00 p.m., October through March. Cost is $12. There is also a large parking garage that is a good place to dump your car and then catch the subway into D.C.