Nice KOA in Port Huron, MI
Huge, almost too many activities for kids and adults alike, clean, nice setting. The only negative for us was that there were so many paid activities for kids that you could spend a fortune or feel like a scrooge for not giving in to your children begging to do the bumper cars, game room, water bumper boats, funny bike rentals, etc. They deliver your fire wood to your site and because of ash borer disease you have to buy it there (ok, another somewhat negative, the bundles were a bit pricey at 7$ each). We did not check out the restrooms or showers but were told by neighbors that they were nice enough. They also have a pancake breakfast (pay) and some free activities like a DJ at night and movies for kids at the Opera House. All in all, it was a great family place. I don't think I'd be thrilled if I were looking for peace and quiet and wilderness, but their demographic is families with kids and cash.
We'll definitely be going back but we'll bring more of our own activities (bikes, skates, etc) and discuss in advance what the kids can and cannot do.