First off...CONGRATULATIONS!!
A few suggesions:
I did 80 miles of the Appalachian Trail in Shenandoah last spring...I know you’re not looking to do backpacking, but there are nice day hikes there and in other parks along the A.T.
Went to Gettysburg last summer, highly recommend.
Check out what’s going on in Hershey, Pennsylvania. Of course there’s the factory “tour,” which is neat, but there’s also a theme park, an amphitheater (saw Def Leppard and Heart there last summer) and an Antique Auto Museum that’s worth checking out.
One FReeper suggested the Smithsonian Air & Space Museum at Dulles (the Steven F. Udvar-Hazy Center), and I second that! They have the Enola Gay there, as well as Ross Perot’s helicopter that he flew across the world, an SR-71 blackbird, a Concorde, and the Space Shuttle Enterprise, to name a few. You could easily spend two days in there.
Good luck and have fun!
“Antique Auto Museum” - yes, that’s the Antique Automobile Club of America’s. AACA is HQed in Hershey - the biggest most important car show of the year is there at Hersheypark.