Here is a little unknown for you:
Tiki Tom's Rv park Tiki Island, TX (real close to Galveston). The rebuilt their sites after Ike. They have 30 new full time sites at $385 a month plus pay Electricity. Their overnight price is $35 and weekly is $200. They have lighted fishing piers for camper only (Several of them) It is close to the I-45 into Galveston, well the overnighters are, but you'll probably be running the AC even in December n some days.
I have no affiliation with this CG.
Edited: The Texas Gulf Coast goes from Port Arthur (Northern Gulf Coast) to Port Isabel (Southern Gulf Coast) 460+ road miles. Anywhere particular you are looking for?