We have stayed at this park several times.  The camp sites are mostly spaced out for room, but some can get very wet and flooded during a nice rain.  The paved bike trail in the park starts near the campground, and connects with a bike trail along the Wabash River that goes into nearby Bluffton, and is an easy ride.  The bison enclosure is always fun to check out, and the last time we stayed I actually walked to the top of the restored fire tower to take in the view.  We have never used the lake, but plan on taking some kayaks out at some point.