Last week I brought a group of beginners to Memorial Park to try out some mountain bikes. After taking a while to get used to riding and navigating around roots, they really started to have fun. I can't remember how many times I heard "so when are we going to do this again?"
After making homemade french toast with has browns and coffee for my buddies, I loaded up 3 bikes on the roof of my volvo and took off for houston, a bit behind schedule. It's about 100 miles from my house. It's really easy to find.
The trails aren't terribly hard, but there are plenty of roots that can make things difficult for a beginner. I definitely think a 29er would give you a better ride here.
We rode until we were so worn out we couldn't. It was a blast.