> is it possible to cross the west ridge of Mt. Russell and drop down to Arctic Lake

Shoot, I was so focused on the "drop down to Arctic Lake" part, I missed the Mt Russell part. Actually, one of the main routes up Mt Russell is the south slope, just west of the Whitney-Russell crest. So if you descended that, it would be quite easy to then head down to Arctic Lake. That Mt. R slope is a major talus slope. The west ridge looks way too steep, but that south slope will work, although tougher with a backpack. Make sure you study the climbing guide books to make sure you find the correct descent route (near the summit).