Me again: I just remembered something. I used to rock climb, and around 20 years ago I did the East Buttress route on Whitney, which has the same approach as the MR. We were traveling extremely lightly, and I'm pretty sure I wore my tevas for the approach and descent. At the time I didn't own hiking boots, and my tevas were my summer approach shoe. I remember running down the JMT on the way back, and twisting my ankle (and then having everyone I passed, pass me, as I was sticking my foot in a very cold stream). Now I use poles for descending, and won't be running down trails in what's essentially a sandal.
All this to say, I'm sure it's doable to use trail runners for Whitney, but is it advisable (since I'm older and presumably wiser)? Also, any opinion of doing the final 400 in trail runners. The ones I bought have a stiff and a grippy sole.
Thanks! K