We were there two weeks ago with the Heart of Texas Camping Unit. The camping area itself is like any RV park with spaces fairly close together with no visual separation. The sites are concrete pads with a nice table and lots of well-kept grass (clover, actually). The restroom/bathhouse was clean and functional. The photos on the website are fairly accurate. Matagorda, the town, has little to offer for the shopper, however a few restaurants exist and the seafood is excellent.
Activities: walk on the beach, rent a kayak (or bring your own), hike some trails, fish (lighted piers), swim, check out the Nature Center, watch birds. It was windy while we were there and the jetty was under construction, so lots of big trucks and construction equipment were running up and down the road adjacent to the park. My grandsons thoroughly enjoyed watching that activity. The park stayed full with the exception of the day the last big cold front blew through.
Hope this helps. Paula