There is literally nothing before immigration and customs.

One Flew South is a decent restaurant, but I think people in this forum tend to oversell it.

If you haven't been to the US before, you might want to try something more regional. Paschal's (in B) is really good southern American food (some in the north would call it "soul food"), one of my favorites in ATL. There's another place in A that is very similar (Low Country).

Where are you staying in RDU? There are some really great restaurants in that area.