The road to CWL campground is sketchy enough, not sure how safe it would be to travel in winter. Being from SEA, I would think a night or two at Tuttle creek CG would be beneficial, and you can day hike up to the Ashram or up some of the slopes around Mt. Langley, etc. All while being able to eat well in Lone Pine to fuel up for the trip. If you are camping on the mountain at all before a summit push, I would think you would be okay from an acclimatization standpoint.