Tyler - I don't know about hobby shops/train stores in the DC area, but i second SJC's comments about Washington being a great place to visit and sight-see. Lots of things to see and do- including the Union Station a few blocks N of the Capitol, which was beautifully restored in the late 1980's. If you are into airplanes, the Air and Space Museum on the mall is a good place to go - better (but harder to get to) is the Udvar-Hazy museum near Dulles Airport. It holds many of the Smithsonian's collection of aircraft of all types, including one of the space shuttles.
The B&O museum in Baltimore is a short train ride from DC and has a lot of interesting displays. Most of the 'old iron' of interest to me is stuffed into a couple of tightly packed 'sheds' next to the roundhouse - so not as well displayed as the PA museum near Strasburg. Still some good B&O and C&O locos. I think one of the articulated engines was pulled from there recently to be either restored or at least 'refurbished' - someone on this forum will know...
