Your choices in that area are probably the Corpus public marina, Island Moorings in Port A, the Port A public marina, Cover Harbor in Rockport or Key Allegro in Rockport/Fulton. When we cruise that area, we tend to hang out in Aransas Bay rather than CC Bay, so I like the marinas between Port A and Rockport.
Port A is the most convenient area--lots to eat, crossroads between bays and access to the Gulf. I'm not sure about food in the Island Moorings marina. Never been back in there. But, there are lots of places at the public marina; Virginias is our fav.
The CC public marina, IMHO, is pretty basic, but being in the big city does have some advantages. But, we tend to just head up the ship channel to Port A and Aransas Bay as soon as we can. Although, anchoring out around Shamrock Island is a nice place too.
I really like the Rockport area and it's easy to pick up the ICW there. I just think it's prettier and less crowded there. If I retire there, I'll probably buy something back in Key Allegro. There's a little spit of land seaward of Rockport called Paul's Mott. Nice secluded beach.