This is a great alternative to the Janet's Cabin Approach
(which isn't bad itself). This route starts very high, at Vail Pass, and quickly climbs 1,000 ft right to tree line. From there, it's relatively flat and, if the weather is good, has nonstop spectacular views.
This route is not as popular, so expect to have more difficulty than normal with route-finding and trail breaking. This is best done in clear weather, and with good navigation skills!
From the huge Vail Pass parking area, head up Wilder Gulch a short ways from the south end of the parking area. Once across the gulch, follow the broad ridge to a shelf at 11,280' - a bit before tree line. Head south, off the ridge, and climb to tree line on a small saddle point. Once they thin, try to maintain a level elevation and keep tree line just to your left.
Janet's Cabin is right at tree line, so you'll hopefully come right to it, but if not, keep an eye out in Guller Creek drainage before going into the trees.