There is a boot packed trail up to the top of the Sherwins from Lake Mary Road. You can park at the outlet of Twin Lakes and hike up the left side of Lake Mary Road until just past the top end of Old Mammoth Road. You will see the bootpack start up the lower end of the ridge and continue up through the old mining claim, across a talus field, then up a small gully to the top of the ridge.
The wind keeps the ridgeline clean of snow, so the walking is good for quite a way, then you can put the skis on when you need them. You can scout the many descent routes from the ridge, including the ever popular avy path and Rock Chute.
The bootpack route is typically pretty safe from avy activity, but I have seen a slide or two there in extreme conditions. I would not worry about hiking it with a foot of new snow. I can't recall all of the details of the ridge beyond Rock Chute, so maybe there is some danger there. In big snow years, snowmobilers have made it to the top of Pyramid Peak.
Something to think about while you are up there: There was an article in the local paper that said geologists had been looking for proof that the earth's magnetic fields had, at one time, been the reverse of what they are now. The proof was found up there, when they found rocks that had been created with the reversed magnetic fields. I probably have butchered their theory and all, but it's more interesting the way I remember it.