another option
stay in Wawona. Drive early to Glacier Point. Hike Half Dome from there. In some ways, the views are better, only view issue is missing the Mist Trail and Nevada Falls from below, but you can do those separately as a day hike on another day
Altitude change up and down is surprisingly the same as starting from Valley floor. Rather than all-up one way, then all-down coming back, this route has ups and downs. Did this in 1993 when my sons were 9 and 11 yrs old. Took us 14 hrs round trip. Long slog at end of day coming back up to Glacier Point from Illouette Falls.
Advantages: cooler, less congested, is an alternate experience if you have done Half Dome before.(Obviously-last part is same)
Disadvantages: Where to stay? Closest to Glacier Point trailhead is Bridalveil Falls Campground on Glacier Point Rd, but I know nothing about it. Check it out. We stayed in cabin in Wawona, Yosemite West has condos, both these may need 2? night minimum and cost more than camping or Curry Village tents. Also, need to drive to trailhead rather than walk.
Just an option.
