If it's done in early season, and you're on the Reid Glacier at first light, it's possible climb Sandy in a day. But you'd better bring lots of GU and Gatorade and really motor. I think it's a little safer cause lighter packs make for better climbing on the steep stuff. The other alternative is to camp at Illumination Saddle, leave your stuff there, and retrieve it with a detour going down the south side.