Yes the Chiwaukums have fantastic skiing. Longview fiber owns most of the land N. of the winderness boundary. I've accessed the area in the spring via the Scottish Lake Resort -- which gets you a snow machine to 5000ft, but to a location further east of whitepine creek.
www.scottishlakes.com
If the drainage you desribe is the one I'm thinking of ... I saw two climbers ascend it to the ridge (and on to the 7400 ft summit) this April while I was skiing in the area (from the resort).
