I would strongly recommend flying in and not renting a car. Parking is so expensive, and sometimes difficult to find, that you would save a lot of time and money by using Uber or Lyft to go everywhere.

The Grand Hyatt is in the best location for sightseeing, but the Hyatt Regency in Bethesda is right on top of the Metro and has a number of good restaurants and shops within easy walking distance. I'd also suggest Crystal City, which is close to DCA and a very quick Metro or car ride into downtown.