Rock Dog is a great place to crash for the night or weekend if you have your eyes set on climbing some Austin Limestone. It's right down the road from Reimers, and is close enough to Austin that you could go in to the city for a meal. They have crate stacking, slacklining, and community campfires. Restrooms are simple portapotties, but you get what you pay for.
This is a good place to camp if you're climbing at Reimers. It's a simple campground and people just drive up to wherever they want to camp. I drove up pretty late in the evening and had to navigate my way through several tents already set up. Nothing fancy, but I'd go back.
To spend a weekend climbing at Reimer's Ranch (Houston's closest crag, 3 hr drive) you would have to stay at a park that is about 45 min drive out of the way. When 3 climbers bought this land together, that issue was remedied. Located a mere 15 minutes away from the crag, early mornings aren't so early and late nights can be later. I've been here a number of times and every time its a different experience but late nights, big bonfires, great community and clean Porta-potties are a constant. There are no campsites per se, just drive in and find a spot with a polite amount of room and set up before joining the festivities. October-April can get a bit crowded due to climbing season, though my personal bubble hasn't been ruptured. I've done both tent and hammock here and the plethora of trees combined with Texas' typical warm nights and the extreme comfort make the hammock my favorite net for catching z's. Overall, this is an overnight camp only, this is not a park and there are no trails but its a convenient and pleasant place to camp if you're looking to spend time at either Reimer's Ranch or Hamilton Pools. By the way, this place got its name from the rock loving dog, Major who roams the camp and doesn't mind other furry visitors.