Algonac State Park

While it's right by the river, you'll need to cross a somewhat busy street to get to the river. There wasn't much else going on there, but to be fair we didn't spend much time there during the day.
The spots are averagely spaced but more on the small side. The site wasn't super unlevel but it was a little short for our 27' Airstream and truck to both fit.
It rained while we were there and the site across from us completely flooded. They had a crew out pumping the water and digging a ditch to drain the water away from the rv and truck that were staying there.