Prophet, I once downclimbed almost the entire upper Lyman Glacier on Chiwawa. I got to be the last guy down, leading from behind, so to speak and lugging all the pickets, screws, etc. they put in. I felt like the "junk guy".
Matt, by "crux" on Rainier, I don't think we mean technical crux, but danger crux. The higher you go, the greater the danger, from weather and altitude. I strongly disagree with DPS's assessment.