I recently move from that area. Plenty of places to ride near D.C. on the Potomac. Great place to launch just north of Reagan airport. Go north for some incredible views of the monuments. Plenty of other places to launch in Alexandria, on the Maryland side or farther south on the Virginia side. Our personal favorite was to boat at Lake Anna which is about an hour an a half southwest of D.C. Also, Chesapeake Bay is 30 minutes away also. Lots of options.