Amazing hike.  It's up there with San Jacinto for my favorite in the area.  I definitely felt the elevation after about 9-10,000 ft!  Next time maybe as an overnight trip to have some time to acclimate.  The first mile or two after you cross Mill Creek is the hardest, both up and down.  Other than that it's pretty steady except a couple sections and there are some nice flat sections in between the switchbacks and hard climbs.   I wandered through the boulder field towards the summit more than necessary because the trail is easy to lose.  The day was gorgeous and clear, and views from the summit were amazing.   Wish I could have stayed there all day!