DC is awesome. Definitely Cherry Hill RV Park in College Park MD. Take the bus to the train into DC then buy a trolley pass. In July and August it is very very hot. Go early in the morning and do inside things in the afternoon. Looks like lots of construction on 270 going into DC and the traffic is terrible so plan your trip during non rush times and allow extra time once you hit the area. There is an Air & Space Museum annex at the airport for The Smithsonian. Worth a few hours. Changing of the guards at The Tomb of the Unknown Soldier in Arlington Cemetery is a must.