Secluded and gorgeous, no longer free but worth it!
This campground is just as remote as others have mentioned. No cell service, miles of dirt roads winding through old farmland and logging roads, and an incredible view of the Crisp Point Lighthouse if you're equipped to make it down the 12mi dirt/sand mixed-vehicle road (I made it with a minivan, but it was real hairy in some spots). Camp itself is right on Bodi Lake with some secluded sites and some closer together that would be good for a group. I was the only person in the campground all weekend. Also, this camp is no longer free and costs $15/night with an additional recreation fee for vehicles (first come, first serve).
Site9
Month of VisitMay