Mauthe Lake is a great campground for both family camping or friendly adult camping. Each campsite comes with a fire pit and grate, as well as a picnic table. Sites are spacious and clean. Showers are warm and clean.
Sites 522 and 523 make for a perfect "group" site without the group price. Book them together and you have an instant party pad that fits 12 people. 522/23 are also in the upper corner of the park so it's a little more private. You get a similar effect with sites 508 and 510 but much more foot-traffic.
I love camping at Mauthe in the fall while the leaves are turning. As it starts to cool, the crowds thin out. We've camped while being the only (party) group on the entire upper-500s loop. It's fantastic! I also prefer camping at Mauthe in the fall because the hiking is lovely. I don't miss the swimming because the lake and beach are small and not great for sunbathing or wading. It gets VERY crowded.
There is a general store just outside the park gates and they have anything you could possibly need in a pinch. Owners are very friendly and helpful.