I can not offer a whole lot since I'm obviously not from that area. However, we have flown to San Antonio several times and will again this April. We absolutely love Texas and it will become our snowbird (winter Texan) destination in a couple more years.
We have seen all the major attractions in San Antonio, as mentioned above, and have been to Rockport and Corpus and over to Del Rio. It's all great and worth seeing. Texas is a huge state and would take a lifetime to see it all. But, what impressed us the most, from the very first time, was how welcoming and friendly the people in Texas are. Enjoy your time there!