I think it would be fun to go out hiking with a group of paleo folks that are interested in pushing themselves, and turning the hike into a natural obstacle course.
I've been out to Pedernales Falls a few times, and there are a lot of large rocks along the river shore to make the path challenging.
There's also “The easy, 7-mile Wolf Mountain Trail (that) wraps around Tobacco and Wolf Mountains, winding along the small canyons created by Mescal and Tobacco creeks.” I haven't taken this trail yet.
Here's a map of the park:
Admission to the park is $5 per person. Bringing along water and paleo snacks to share is suggested.
The gameplan is: Meet up at my place at 10am (which is near Cafe Express and easy to find), figure out how many vehicles we should take to the park, drive out Pedernales Falls, explore the park to look for the most fun and challenging paths, then head back after a few hours.