The Adams Morgan District is very high crime now. If, you have a decent looking vehicle, you could overnight in Georgetown. Hospitals are your best bet. Providence Hospital is very tolerant and the streets around it have unlimited, unmetered parking. From there, there is a 12 minute walk to the metro and you can access everything. If not, you will not get anything north until you hit Takoma Park and Silver Spring for free, safe parking. Takoma Park has turned into a low-class, seedy area, but around the Adventist University and Hospital is wide open parking if you rotate your vehicle. It is also a 3 block walk from a very small park where ample, clean water is available. If you are willing to pay and want to be in the center of action, there is a o.k. price, well-monitored, open parking lot 3 blocks north of the civic center. Crime is insane anywhere else. Watch your vehicle and lock it. Don't park in Georgetown on Friday or Saturday night. Every other hospital south has very high crime rate, but is safe in the daylight. I would drive out of D.C. and overnight in Northern Virginia or Maryland at night and then use the metro or drive into D.C. for the day if you use any base other then the Providence Hospital area. Remember one tip, no one with money stays in the city at night.