High Sierra Topix

backjassett- have you actually done that route? Your mileage seems optimistic to me.

I did it in June 2021. It was initially supposed to be a five-day trip, but I accidentally hiked the first three days (N1 Cascade Valley/Purple Creek JCT, N2 Lost Keys, N3 Peter Pande) of my itinerary in two and had extra time on the Tully Hole leg to explore east because I was ahead of schedule. I only suggest what I actually accomplished because OP mentions he likes "physically challenging" 15-20 mile days.

Backjasset - Great loop! You did leave out something very important on Day 1. You left off soak in the hotsprings at the end of the day. A soak, especially in the upper hotsprings with the view down the canyon is a must at the end of a day of hiking IMO.