Garner is beautiful
I'm from San Antonio and I grew up going to this park almost every summer of my childhood. The Frio River is generally pretty low but it is clean and clear and there are some deeper parts to it. I think these areas are mainly towards the older camping grounds. I like the new camping sites they built towards the north because they are bigger and more spaced out. I think Rio Frio is the newer part of the park. Enjoy!