We have an RV, but our trip at the end of Sept we flew and stayed at a motel just 1 to 2 miles from Mt Vernon. What we did, even though we had a rental, was one day we took the Metro into town and visited the Holocaust Museum. The next day, we hired Brian, with Bipartisan Tours, to take us down town to see all of the monuments, library of congress, embassy row and other sites in Alexandria and Georgetown. He picked us up at 8:30 in the am at our motel and dropped us off at 6pm. Cost per person was $85 per person. Even if we had taken the Metro, many of the sites are too far apart to get to on foot. He drove us up, let us off, parked the van, 11 passenger and we only had 7 people and then told us history about the site we were visiting. Well worth the money spent and an excellent guide.