Really nice state park and campground. Sites are $30/night, and they all include 30 and 20 amp power. Dump station and water fill is available at the west campground entrance. You also need to pay a $11 daily state park fee, unless you have the $39 annual pass. The fee gets you into the state park area, and the fort was worth exploring, it's really nicely set up.
There are two separate campgrounds, east and west. We drove through the east one first and immediately hated it. Sites are open, no division between them, kids running around everywhere, big groups of people, just overall chaos. So we went to the west side and liked it much better. More tree coverage (which was fine because there’s power and we didn’t need the sun for our solar panels), sites had way more division between them (though far from completely private). There were still lots of kids and big families on this side but it was overall so much more quiet and pleasant.
If you’re in an rv and levelness is important to you, then I’d really try and not make reservations, but pick a site when you arrive. Some sites were completely level, some were fixable with levelers, and a few were straight up on a hill. Though the campground has lots of trees and narrow roads, we saw some huge class As and 5th wheels rolling through- there are a bunch of massive pull through sites here that made it easy for them I’m sure.
No cell service in this entire area but there’s free wifi at the bathrooms, which weakly reached our site that was several spots away from the bathroom. Nice free hot showers that run like normal (no button to push every 10 seconds). Trash bins but no recycling (Michigan is surprisingly bad at offering recycling!). Host set up is very nice, with a ton of brochures and info and free coffee every morning!