Is this a crabbing vacation, or a vacation you'll spend a little time crabbing?
If it's the 1st forget OC. Head south at Salisbury and go to Cheriton Va. Cherrystone Campground has some great crabbing in July and August.
If it's the latter... Well, one spot is as good as the next. Maybe try asking a few folks where they're running when you get down there. Good luck and have fun.