We live not too far from you and we have been alternating between Hilton Head and Virginia Beach. Last year was a Hilton Head year but we couldn't find anything exchanging through II or RCI (with an 18 month search) so we settled on Myrtle Beach. While Myrtle wasn't bad, the weather wasn't as nice as we have had in Hilton Head. It was similar to what we would have had in VB. It was a much further drive for VB type weather and while it has a lot of activities , they were more expensive and less educational based. We like VB at that time of year because even if it is rainy and cooler we have enough between Williiamsburg, Hampton, VB, and Norfolk to keep us busy both indoor and out when the sun doesn't shine. In Hilton Head we love spending time on the water, dolphin watch, kayaking, etc and riding bikes and spending time outdoors.
We like OBX in the early summer but I've always been afraid that there isn't enough indoors in case it is too windy an cold in the spring.
If you can't get VB at this late date Williamsburg is usually a fairly easy alternate. You can always do VB as a day trip during the week if you know one day is going to be especially nice and the rest of the Hampton Roads area is a fun place for nautical type day trips visiting both naval and commercial ship yards and naval history as well as colonial history.