Bugsbunny- Glad that you camped at Bull Run Regional Park. This is a great campground and the best place to camp for access to Dulles Airport.
I just spent a few days in DC visiting my daughter and wanted to put in a good word for Greenbelt Park. This is a great campground, operated by the NPS, and is wooded, very private, never crowded since there are no hookups,and located about 12 miles from the museums. It is also cheap @ $8 if you have a senior pass. I found driving to DC to be just fine- take the Baltimore- Washington Parkway to 295 to 395/695, exit at Maine Ave and park at the Tidal Basin. You may also find a spot on Madison St. behind the Natural History Museum. Get there early and parking is for 3 hours only but it is free. For pay parking, use the parking garage at Lenfant Plaza. I just drove my truck into DC, parked and used my bike to get around. There is also a Metro Station about one mile from the campground.
I have two recommendations for food. There is a food court at Lenfant Plaza and great seafood at the fish market at the fish warf, Jimmys Grill. Their two piece seafood dinner will feed two adults. Try the sauteed spinach for one of the sides.