Stayed there for a day and there was plenty to do.  From the beach, to the splash pad, the huge playground, the hiking trails, fishing in the lagoon, and the touristy attractions right down the road (i.e. - bumper boats, mini golf, batting cage, go karts, etc..).  The kids had a blast and are wanting to go back again.  We were there in the middle of the week so it was not packed or loud.  It is located north of Bay City by a little bit, so if a night out in the city is what you want it is easy to do.  It is right on the Saginaw Bay so there is a lot of fishing that can be done out there too.  The campsites were the normal state park campsite fare.  Overall it was a great day.  The only downfalls were that there was a bit of construction in park going on and the beach wasn't of the all sand variety.  A bit of small rocks and a lot of shells, plus the water was a tad murky but nothing major.  If you are looking for the great outdoors, in the middle of nowhere camping, this is not it.  But if you want a fun time with the kids, I would recommend it.