As you can see from the Map, there are only a hand full of Campgrounds.
There is a CG showing by College Park, it has no power or anything. Even if you wanted to boondock there it is REALLY tight. The one in Lothian MD is about 1/2 as nice as College Park. The KOA in Millersville, MD is OK. It is between Baltimore and DC and close to Annapolis, MD. Not sure about the VA CGs.
I grew up around DC all of my life. PM me if you have any other questions.
Where in California are you? I am making my way there right now. I am NM right now heading West.