I'll echo some of the remarks from above. Worth noting is that Katfish Katy's and Cooper's Landing both have live music in the summer.

--Katfish Katy's is a great place and I believe that their general store has different owners. This past summer the store owners were a young couple that was very awesome.
--Cooper's Landing is a marina/campground that has a food truck on site with the best Thai food that I've had in a while.
--Turner Katy Shelter is also a good place to stay especially if you want to shower or enjoy some air-conditioning. Cost is only a small donation but you may want to have food with you, unless the new pub is open next door. It was under construction last spring.
--Hermann City Park was actually a very nice park to camp and an short distance from downtown which has some great amenities (like a meat shop & a brewery)