Just wanted to let people know ---- If you have any specific questions about the area I may be able to help. While not in Austin for college, I live in Aransas Pass pretty close to the ferries going into Port A. I have a few friends that went to highschool there as well as my girlfriend worked for some condos that are pretty close to the beach. She's used to answering a lot of questions about the area.
I know that the cops are cool as hell haha.. (At least they were this past spring break) I would also get gas in Aransas Pass. It's typically a lot cheaper than Port A (same thing for groceries). I've camped on the beach a few times and never had any problems with theft or anything like that. It is also pretty typical for people to bring their campers onto the beach for a few days at a time if anyone was wondering.
Wish I could make it, but I'm still pretty new to stand up's.. I'd probably eat it pretty bad in that surf.