Without question, what you want is a private campground called
Odetah Campground.
It's in the town of Bozrah, about ten minute's drive from Mohegan Sun.
We've stayed there A LOT, over the years. Multiple, large, clean, well functioning restroom locations with showers and changing rooms, all over the site. They have cabins, Yurts, tent sites in the woods and by the lake. They have a pool and hot tub. A huge playground, tennis and basketball courts. A country store and new eating area by the lake that provides breakfast, lunch and dinner of you need.
They've got canoes, rowboats and kayaks to rent. Mini golf, horseshoe pits and a beach. Fishing and pets are encouraged. Every weekend has a themed set of activities to do for and with the family. Most are included with the stay, but some ask for a couple extra bucks, if food is included.
It's HANDS DOWN, the best privately owned camping facility in the state. And we've stayed at all of them. There's no comparison to Odetah.
Do you have a pop-up/camper, tent or need a cabin? I can tell you which are is best for your needs. I know the place like the back of my hand.