My wife and kids all hiked with me, we took our time and let the kids play and  still completed the hike in well under four hours, this area of the hill country may be the prettiest I have hiked. Clear streams, almost no one in park during the week, only a few swimmers in the creeks. We stayed in cabins just a couple of miles from park, but I can't remember their name, just look up vanderpool cabins and I am sure you can find the information.