We stayed in one of the yurts, and I was perfect for the group of 6 I went with. It dumped rain the first night we were there and the yurt kept us perfectly comfortable and dry. There is fishing, boating, hiking, and all sorts of activities to do around the park. We rented a pontoon boat for one afternoon and explored the lake, which was awesome. I will say the "beach area" we visited was less than clean and quite small. However, the trip was a blast overall and if you're looking for a quick weekend trip, this is a place to go.
There is anything imaginable to do up here from biking/hiking to amazing geology and fossils to whitewater rafting/kayaking all the way to camping in all forms. We stayed at one of the walk-in campsites and it was the perfect mix of convienient yet secluded. Tons of wildlife and nature for any interest. Be sure to check out Cucumber Falls and the natural water slides! Some absolutely amazing geology there and stunning views!