I have never been to RGV but it does not sound like it has much to do. Just warm weather is not enough of a draw for me to come down and sit inside my RV.
What activity's are there for people in there 50's? In my summer seasonal site I have a UTV with trails to ride on. A chain of three large lakes to take the pontoon boat on. Lots of scenic roads to ride the motorcycle on. Lots of trails to take the Collies for a walk on.
Are there any parks that cater to the active lifestyle?
It sounds like my parents would have loved the Big Band and dancing but they passed away 20 years ago.