If you hit DC between 10 and 3, you should be fine. If not, I would consider taking U.S. 13 south down the DELMARVA (Eastern Shore). You'd have to pay the $12 toll on the Chesapeake Bay Bridge/Tunnel, but you'd miss traffic and it is a beautiful ride. Basically, after you get across the bay, you'd take I-64 West to Richmond and back to I-95. U.S. 13 is a divided highway down the DELMARVA, but watch your speed as it is usually crawling with police.