For a route from Philly to DC, have a look at this journal: Turkey Tour, Touring out of Washington DC on Thanksgiving Weekend. (I also have a Boston - NYC tour journal up on Crazyguy.)

Once you get out of northern Delaware, the route I followed to DC makes little sense unless you have to be in Columbia. When you leave Bel Aire, I'd look west for navigable roads, then head south into DC. In particular, my route from Columbia, MD to DC was pretty bad. I don't think they know what a bike even is on the roads near Columbia.


This is, unfortunately, fairly typical of most roads in the Columbia, MD area

Northern Delaware is a climber's paradise! It's beautiful, which I did not expect. The drivers were all polite and passed at safe distances. I'd stay as far from the coast as possible, though.


West Rolling Mill Road in Wilmington, DE

I stayed away from Baltimore, circling around the city limits.