Northern Virginia

Hyatt Dulles and Hyatt Place Dulles East (I think it is the East one) - perhaps 10 minute walk through suburban wasteland.

District of Columbia

Grand Hyatt and Hyatt Capitol Hill - perhaps 10 (short) block walk

Hyatt Capitol Hill and Hyatt House New York Avenue - slightly longer 10 block walk, part of it in "redeveloping" environs I, a 45 year old man, would not make at night, or a one stop trip on Metro's Red Line.