GREAT FALLS NATIONAL PARK
Great Falls is just a few miles north of Arlington on the Potomac. I biked out there on the C&O Canal towpath back in July. It's a beautiful park with a nice boardwalk to view the rapids and watch the kayakers run through. The C&O Canal runs from DC up through Virginia and I believe on to West Virginia and into Pennsylvania. Apparently, it's bikable with towns to stay in along the way.
A dog!
Another dog!
And another dog!
Maybe she could model for the vegan's alternative to Santa's Rudolph? I'll contact PETA.