I've done it in late June with as a team of three over three days. Last year I did it by myself in early August over three days, but I stopped short of climbing the last summit rock part. I would say that late June to mid July are the best times to climb it. The year that I did it in June, it was a big snow year and so there was basically no crevasse danger. The crevasses were just inches wide. We did the scramble version and then rappelled from the top (bring some webbing and a rappel ring).

When I did it last year, the Blue Glacier was pretty rough. You could accidentally get wedged in there and be stuck. So before you cross the Blue Glacier, you want to walk a little more to get higher up onto it and then cross. Then I scrambled on rocks before getting onto the snow leading to snowdome. Before getting onto snowdome, my leg punched through a little. Once on snowdome it's pretty flat and you go straight and take a left to go behind the rocks. In the back part, I had to zig zag about four times around big crevasses (which weren't there when I did it in June). Then a short rock scramble up near I think the center summit and then scramble down and then go up the snow ramp to the West Summit.

http://imgur.com/a/GFrSn First picture is from the Lateral Morraine, after Glacier Meadows. Second shows the last climbing part. Third is what it looks like from snowdome. Fourth is from behind the mountain. Fifth on top of the Blue Glacier. The first time, we were on the mountain alone. The last time, I was on the mountain alone. When I left there was another guy who was going solo. I never found out if he made it. Three days is probably as fast as I'd want to do it. The last day out feels hard.