My friends and I did DC to Pittsburgh every couple years when I lived in Pittsburgh and it's a great gateway trip to see if you like bike camping.

Not sure about your fitness level but if you can handle a 75 mile ride and have a three day weekend in the summer you can ride from Pittsburgh to Ohiopyle, camp at the state park, spend a day doing rafting, natural water slides, Fallingwater & Kentuck Knob, etc, and then come back on the third day. (And for folks who don't like sleeping on the ground there are hotels / B&Bs there too.)