I would highly recommend the Guadalupe River RV Resort in Kerrville. You can find a link to their website and pictures of the park that we took during our month long stay there a few years ago
here.. Great area with many things to see and do! Rates were very reasonable and it is also a good jumping off spot to visit other hill country attractions and areas. We will return there some day.
I would recommend making a reservation but they had numerous open sites all the time we were there in March.
Barney