Sorry for the very late response...
We went to the Medoc Mountain state park yesterday, the weather was not perfect, but we went anyways to scout the location.
The park has a very nice, big open field, however the tree lines seem a bit too high, you won't be able to see much of the horizon (compared to say when viewing from boat ramp on a large lake).
Park officers are extremely nice and friendly. Seems like also some astronomy clubs and groups go there often for stargazing.
Being only 1 hour from Raleigh, I will probably go there very often