If its the area I remember, out Salmon-la-sack I remember going up there camping/wheeling with Toylet and a couple buddies few year back. This was during the summer.
Couple places you needed 4wd, already with old-skool open/open rigs and before we could drive decent. But cool place and trails that wound up the mountain side (bare and open) with mine shafts to check out dotted all over.
I definitely would want to head out there again, but I thought I heard it was all closed/gated now. Maybe I'm thinking of a different fork.
IIRC we went up Salmon-la-Sac road past lake Cle Elum, to the north end, then continued up the road north along the river that feeds the lake. I think it turned into a gravel road with some cabins and various camp sites scattered here and there.
Cool and fun area, but its been MANY years since I ran up that way... be fun to do it again.