All through DC and its environs there are lots of bike trails, good riding on all of them. Then, going north from Annapolis, there is the Annapolis-Baltimore trail, which comes almost to the suburbs of Baltimore.
My route stopped here at Havre de Grace, DE because google maps, in bike mode, won’t let me cross the bridge over the Susquehanna River there. That’s where we put the ELF on a pickup to get it to the other side.