This year is a heavy snow year. In 2011, which saw a huge amount of snow, hikers were finally using the switchbacks about July 9.
Crabtree Pass, at 12k, is likely to have lots of snow. You might want crampons and an ice axe to get over that pass, and probably to descend the main trail from Trail Crest.
By the way, if you go over Crabtree Pass, you could camp at the upper lake, and next day climb to Discovery Pinnacle and hit the main trail from there. It is a wide open slope, and if you can get over Crabtree Pass, this climb will be easier than that.
Good luck, and would love to see a trip report!
