I used to live in MYR and then CLT, and have all these highways burned into my brain.

Depending on how fast you drive, RDU to High Point will take about about 1 to 1.5 hours. (longer if you're coming from Raleigh, shorter if you're coming from Durham).

The problem woudl be going from High Point to the coast. That will be about 4.5 hours or more, I think. (This is assuming normal traffic, as well) Depending on which beach you go to, you might backtrack on the same highway you took from RDU to High Point. (I-40).

I don't know your endurance, but I would likely pick one or the other - the western side (High Point) or the eastern side (beach) - and not try to cram in both. (and i used to drive from NC/SC back home to WAS/NYC pretty regularly)
If you left Sunday morning from High Point to the beach, you might be able to enjoy a couple hours of daylight at the beach, but not enough to make it worthwhile (i think).


If you pick the beach, keep in mind the Outer Banks and MYR have much different feels - the Outer Banks is more about rustic beauty. It has lots of lighthouses, etc.
MYR is the self-proclaimed redneck riviera. it has lots of mini golf courses, chain restaurants, etc.