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