Just have to add in, as a native of the 'burgh, it is a wonderful town and you'd really enjoy spending a little time there. Though with all the hills, biking can be a challenge. I mourn the young me who used to be able to bike around there with no trouble.

I believe here was just a bike ride from DC to Pgh that I believe ended in Pgh to celebrate the 250 yr anniversary of the city.

http://www.atatrail.org/ <---- info on the GAP