Sorry I don't have directions, but here is what I remember of my trip there about 8 years ago or so.
It's an awful long drive. I hope you are going to take a break and get a hotel to grab some sleep or maybe have multiple drivers. I did the drive back in college from Tiffin, OH, to the Outer Banks. Actually stayed in Cape Hatteras. I think it was like 14 hours??? The worst part of the drive, oddly enough, was once we got to the Outer Banks and had to drive all the way from the top of the Banks (somewhere north of Killdevil Hills) down to Hatteras. OMG that sucked.
But it's a nice area. Gotta do some kite flying if you go (sounds corny, but get yourself a stunt kite and have some fun). Tour some of the lighthouses...Hatteras, Bodie, and Okracoke lighthouses are pretty easy to get to. Overall, have fun.