I've never RV'd there, but I lived there for 14 years and just came back from a visit a few months ago.
There is SO much to do in San Antonio, and I'm pretty sure you'll love it. It's a really wonderful city!
Sea World, Fiesta Texas, the River Walk, the Alamo, Japanese Tea Garden, Natural Bridge Caverns........some out-of-this-world Mexican food and BBQ.....great people.......
Spend some time at one of the tourist sites for SA and start making your list.