Hi, Deke.
It sounds as if you've done quite a bit of reading and your instincts are solid. Here's my two cents:
- During the summer, the afternoons are very hot up at Trail Camp and there is little to no shade available. Since you plan on sleeping there, there is little advantage to reaching there much before late afternoon.
- I would plan on an overall speed as slow as 1 to 1.5 mph, breaks included. This would be true for the lower half (with packs, climbing up from the portal) and the upper half (without packs, up to the summit). So figure 4.5 to 6 hours--probably closer to 6-- for each section. Coming down is obviously much different and less of a concern.
- I would leave the portal at about 11 am on Thursday for the hike to Trail Camp.
- 5 am on Friday should be an early enough start to avoid being up high when storms are most likely to hit, but consider a 4 am start in order to get down off of the switchbacks a little earlier, again, because of the heat.
- Finally, since you do not need an early start up to Trail Camp, make hiking and sleeping at Horseshoe Meadow your Plan A. It's higher, which helps more, and the day hikes are gentler.
And the good news is that you all might do really well at altitude and be faster than I predict. I am just giving you what I think are conservative guesses.
Above all, have a blast!
