I would do I-75 to I-64 to I-77 to Rt 52 to I-40 to Rt 64. This takes you over to West Va, to Wytheville, VA, down the mountain to North Carolina, then across to Raleigh, then to Rocky Mount, NC and on toward Manteo and Nags Head. I didn't know exactly where you were going in the Outer Banks.
We did this route from our home in SW Virginia to Nags Head in a 24-passenger bus, pulling a 12 ft trailer a couple of years ago. It was fine, except there is usually lots of traffic going UP the mountain from NC into VA on I-77. Usually southbound is okay.
The other routes take you up I-81 with all the heavy truck traffic and then on through Richmond, VA and then into the Norfolk/Virginia Beach, Portsmouth area and the traffic around there can be horrendous. The other is just my preference and others may have a different opinion.