@zenhabits13, looks like you got a great suggestion below from @lauralie. If you need additional ideas but don't hear anything back here, you could always call our Portland, Olympia, or Tacoma REI stores - our local employees often have some of the best recommendations!
If your looking for reservable- Mayfield Lake is a gem! Book early and you can get a site right on the lake. It’s run by Tacoma Public Utilities, super clean, showers and a beautiful lake where you can swim or fish.