I live in Texas City, TX, 40 miles South of Houston, 14 Miles East of Galveston, but on the mainland. There are a lot of CG's in the area, but not to many right on the water. Via Bayou RV Park, Dickinson, TX is on the Bayou that empties into the Gulf vai the Ship channel. I little pricey, but then it is on the water and a nice spot. About 18 miles to Galveston, and still about 40 miles to Houston. Forty miles to Houston is a 50 minute drive except in high traffic times, then it is 1 hour to 1 hour 15 minutes - depends if there was an accident or not.
One I would recommend is Green Caye RV Park in Dickenson. Very nice park, Nine hole par 3 golf course. Monthly rate is about $375 and includes electricity (FHU). Again, about 35-40 miles to Houston.
On I-45 (Gulf Freeway) there is Adventur Out, Dickenson, and Space Center RV Park, League City.
The easiest way to find CG's in an area is to Google search on "Galveston Campground" without the quotes. You can do that for any city and get a quick list of CG's in that area, then call to see if they are still in business after IKE.
Wayne MSGT USMC (Ret) & Earlene (CinCHouse)
2008 Winnebago Destination 39W
It is what it is, and then it is what you make of it.