Keith,
You'll find no shortage of Sandhills recommendations on this website. There are countless threads devoted to the topic.
Pine Needles is hosting the US Senior Women's Open this year from May 13 - May 19. You mentioned that your trip is mid-May. I just wanted you to be aware in terms of course availability, but also to suggest that it *should* be in prime condition. I think many of the green complexes at Pine Needles are world class, and the 11th hole is one of my favorites played. It's had some recent restoration work.
The course clearly missing from your post below is Tobacco Road. Assuming you are flying out of RDU on Sunday afternoon, I would recommend a Sunday morning there. It's a one-of-a-kind roller coaster ride, and, without traffic, is only about 45 minutes from the airport. Pinehurst proper is about 1 hour and 15 minutes, so you'll cut off half an hour from the trip. If you've never played, it is a must experience.
Enjoy your trip to our wonderful state!