This was my 3rd trip to Stillwater in 3 yrs and it gets better each time!
Our first trip was an overnight to test some backpacking gear, it was September and the weather was perfect! We hiked into our site, not easy because almost everything is meant to be accessed by boat so we were guessing our course! Cooler weather meant no bugs to contend with
Next year we took a canoe to our site, it was July, warm weather, warm water and the bugs were not terrible, we were at Site 1, secluded in a cove, not a lot of traffic but there is a hiking trailhead near the site so there is potential for visitors.
Our latest trip was to site 10, an island site with a large sandy beachfront, we borrowed a motor boat to get there this year and brought plenty of gear for 4 days. Weather was great again, some rain each day but we had time to get setup and get shelters to keep dry.
Camping if free here but it is first come first serve but with 40+ sites you can almost always get something. There is a small store at the boat launch to get provisions if you need, public restrooms and wifi. Very limited cell service.
You should bring water or something to filter it from the reservoir. I believe all the site have privy boxes on them.
There are opportunities for fishing, a few local attractions, a nice restaurant at the launch.
Planned this campout about a month ahead and hoped for good weather. Turned out to be a rainy week and weekend, a few dry spells in between. We had plenty of shelter with us to keep dry. My 2nd trip to this park, first time we hiked the trails, beautiful waterfalls and scenery. Campsites are close, fortunately we were alone, probably due to the weather! We were creekside in a nice spot.