The National Mall is about 20 miles from the hotel and is well worth a visit for a few hours. We recommend driving/ubering to the Ashburn metro station and taking the silver line to Federal Triangle or Smithsonian stations for easy exploration of DC.
This is close to the hotel and Dulles Airport. It is an adjunct of the Smithsonian Air and Space Museum and houses the space shuttle and many historical aviation artifacts.
This is across from the hotel if you need something to do for a couple hours.
One of our favorite Wineries in the area