Great Modern Campground
Lots of space in between the sites with trees and such in between, so it has a great wooded feel with modern bathrooms/showers in each loop. Tent pads, picnic tables, and fire rings on each site are all a plus, though you can't move the tables as they're secured to the ground on the tent pad.
Great fishing, paddling, and tubing on the Platte River just across the street. You can rent tubes/canoes/kayaks from Riverside Canoe Rentals just across the bridge (~1/2 mile from the campground) - also a great place to get ice cream.
Plenty of Lake Michigan beaches to drive to. Whether right at the end of Lake Michigan Rd. at Platte River Point, or a bit farther away, there are plenty of options. Can even have campfires on some of them - awesome way to see the stars and a good sunset.
Very difficult to get reservations, though. Online reservations open 6 months before the date you're trying to reserve so be on right at 10am or you'll have to try your luck with the walk-in sites.