You could get there by driving through PA, then through my home state of DE. You can follow I-81 south to I-476 south, then from I-476 get on 95 south. Then get off at the route 1 south exit in Delaware, follow route 1 south until it splits. At the split take ALT 13 instead of Route 1, and ALT 13 takes you right to Virginia beach. I think williamsburg is about 35-40 min. from Virigina beach. I don't know if that'll save you any time, but at least you won't be stuck in any horrendous traffic.
-Mike