Hollister is fun the first couple times. There's enough stuff to do for a day trip, anything longer and it could get boring. But then again, it depends on how built your truck is. I've found for my lightly modified 4runner (read ifs) a lot of things are too easy or too hard, not much inbetween. The obstacle course is fun and so is the rock quarry. There's a bunch of hill climbs and trails to follow. Oh, and don't even think about trying the big mud pit, you'll end up needing a new engine.
