JZ here, your intrepid guide on the OBX journey.
Flying into Norfolk is ideal, next best is Richmond. Avoid Raleigh as it is such a long drive (about 7 hours). In general you are best to pick up groceries before you get out onto the islands, so perhaps in Norfolk or on your way down. However, most of you will have flights that arrive late and you’ll want to just get to Waves. In the am you can grab a coffee and muffin from the coffee bar there and then head either north or south by about a 20-30 min drive to find the Food Lion for your groceries, beer and wine and one of the State run liquor stores for any hard bar you want. I’ve made a map you can bookmark that has all the Food Lions, liquor stores and some other notables marked on it (including a great place for lunch marked as the “amazing sandwich bar”). Here’s the map.
Quick correction to the above (I live on Roanoke Island just north or Hatteras Island)—Raleigh is only about an hour longer drive than Norfolk Airport and about the same as Richmond, and has much easier traffic. RDU to the Bonner Bridge is about 3 hours 20 minutes. Definitely a viable option, especially in the summer when the traffic on US 158 from Currituck to Nags Head can be awful.
Grocery stores on Hatteras are OK, but selection is better at the Harris Teeter in Kill Devil Hills if you’re coming down from Norfolk. Plus it’s on the way, while the Food Lion is a 20 minute drive from Rodanthe going south.
Ocean water can still be cold in May, particularly north of the Cape—bringing a full suit is a good idea. Booties are a good idea for the sound because of oyster shells and other stuff—not needed in the ocean.