I camped a night at Dutchman campground in late September. When I looked online before going, no spots were available per the online reservation system. The system didn't show that the spots were reserved - just not available. When I arrived, I found most sections of the campground closed, and one section open with several spots available. The vault toilets were unlocked and clean. There was no trash service or water. Camping was free. So after the camping season, consider it first come -first served.
The sites are well spaced with numerous trees between. Each site has the expected picnic table and fire pit. Dutchman campground is a bit above the lake and most sites will not have a view of the lake. I hiked down for pictures. No problem with mosquitoes in late September.