Wish you luck on that one. Years ago (20+) that was a decent hunt, open to all Colockum M/R tag holders. That was before many of the upper orchards were started in the Semilt basin (where they don't seem to believe in fences). Since that time the elk (and deer) numbers in all of the Jumpoff area have gone WAY down. I have my own ideas on that which I will keep to myself for now. Though I have not been in the area this year we found that Colockum through Kingsbury, Moses Carr to S Jumpoff were our favorites. Those with the best chance beyond that know some of the orchardists and can hunt the private property on the lower basin loop. Got a mission any buck tag a few years back and didn't see anything for elk in that area about this time of the month. Good luck and get into 'em!
Maybe someone with the knowledge your asking for can help you out before you head out.