Stayed in 'The Best Western, Springfield' last year. Large room, basic breakfast included, very satisfied with what we got for the price. Hotel has courtesy bus which will pick you up and drop you off at the locat metro stop at any time.... Metro is very cheap at weekends and public holidays.
Washington is a fab. city to visit, but not very big, so after you do the city bus tour and have seen everything, it is very easy to walk around the sights you really want to see.
Arlington cemetry is the other side of the river, both the bus tour or the metro stop there so there is no problem, well worth a visit. The museums and galleries are all in the same area. There were a few other hotels also in the springfield area, a bit out of the city, but with the transport system very accessible.
Great food hall in the basement of Union Station, every kind of food available at fantastic prices, so once you have had your breakfast in your hotel you can feed yourself for very little for the rest of the day, there is also a cinema there too.
Deff. worth a visit.
L.