I have stayed here two times with a group of parents and kids when we have biked the Elroy-Sparta bike trail, and I will likely do it again. The campground is great if you want to have a quiet, natural setting without being out in a remote wilderness far from amenities. We put our multiple tents out in the open field part of the park and don't worry about trying to get one of the electrical-hookup sites. There is plenty of room for many, many tents, There is a large covered pavilion with electric for cooking and eating, and clean bathrooms and coin-operated laundry and shower facilities.
Right next to the campground are a pool ($2 entry fee) and two sand-volleyball courts. Add a playground and large open field for soccer, football, or frisbee, and there is plenty to keep the kids occupied. Plus, it's fun to bike around the village to have some pie or check out the old-style hardware and general stores. You feel like you can give the kids quite a bit of freedom to explore around town and they can't get into too much trouble here.
The Elroy-Sparta bike trail is one of the prettiest converted-railroad trails I have seen, taking you through the rolling hills of dairyland Wisconsin. Be sure to bring a flashlight for the nearly mile-long tunnel.