RGV Last Week of June

DW and I are thinking of driving down to RGV (Rio Grande Valley) in a few weeks. We want to spend a few days down there just to look around and see what's down there. Planning to take a day trip to South Padre but don't necessarily need to stay on the island.

What are the attractions down there this time of year?
Recommendations for a nice place to park with attractions close by are appreciated. We will consider anything between Mission and Port Isabel.
Thanks in advance