I did San Gorgonio in a pair of ultralight road running shoes and did just fine - though I wouldn't do it again. The sole was too flimsy. I just didn't have my trail runners with me.
I actually just bought two pairs of trail runners:
Saucony Peregrine 4 and Salomon S-Lab Sense 3 Ultra SG.
(I couldn't decide, so I went with both). The Peregrines have a very soft, squishy sole and the S3Us have a harder sole. Both have a sole plate to absorb and shield sharp rocks.
After doing Whitney back in June, I was talking with a guy doing the PCT and he was wearing trail runners, and said a lot of others were as well.
I usually hike in trail runners, but did Whitney in a pair of boots and longed for my TRs the entire time.
