Jus find Randle WA and take the road south, then whenever the road forks, take the left forks. You will find some fee camping, but look around using the other forest roads. There you will find places to camp. Some of those "roads" are nothing more than jeep trails. Explore and find.
I live in Yacolt right be the entrance. I have to say, there’s been a looooot more armed tweakers heading up there as I see them pass my house every week. Just be careful up there. There’s quite a few disappearances over the years and just overall freaky events.
I came across a tweaker village in the gifford pinchot near willard. 3 old RVs and some shacks. Looks like they have been there a while but signs of recent human activity. Lots of tweakers go up to pick up shell casings to sell for their next fix. I never go out without my X95 tavor