If you can try to get there in the early morning and kill some time before you pick up the keys to your rental (assuming you're renting a house, not getting a hotel room) you'll be a lot more relaxed.
Agree wholeheartedly with this assessment. We've gone every year for the past 12 and for at least the past 4, our routine has been to leave Ohio at 11:00pm so that we can arrive into OBX shortly before 11:00am. We're normally past DC by 4:30am and on our way down the coast.
We've also been lucky in that our rental agency has let us pick up keys early. Even if they didn't, though, it's easy to kill time by hitting the Brew Thru or the grocery stores to stock up on stuff for the first couple days.