You can stop at Ana Reservoir and just camp in any of the fishing spots right off the water, all free. This is right before summer lake. Or go to Summer Lake Hot Springs and pay a few bucks to put up a tent and soak in the pool.
Or get to Paisley, turn up the road(Right up Chewacaun River) and a good 3-4 miles up there are lots of free spots down on the river. Very pretty area.