Originally Posted by
axolotl
It's easy to head toward Skyline Drive from DC--just take the W&OD trail westward. It's a nice, paved, rail-trail. You'll need to first take the Custis Trail in Arlington, VA, for a few miles to connect to the W&OD. The two trails will take you 2/3 of the way to the north end of the national park.
Bit optimistic on the 2/3's, sorry. W&OD runs you only to Purcellville, then you need to get to Front Royal. 1/2 maybe, and even that's optimistic considering it drops you way NE of where you need to be.