I've seen a few 5ers and TT and MH on the sand at Mustang Island near Corpus Christi and Padre Island National Seashore.
I would only go there if I wanted to dry camp on the beach - and only have testing the area before hand without the rig. Including the drive to the site, turning and drive out.
The 4x4 TV might not have an issue - but the TT has a lot more weight on a likely smaller footprint.
I would never attempt a drive-by with a trailer. Just too much risk. And if you get stuck - you likely will need a very expensive heavy duty wrecker to get the trailer out. Which will likely damage the trailer.