I plan on a 0200ish start that 1st morning. I'll have my comfy truck camper parked right at the trail head proper so I just need to roll out of bed and hit the trail.
I have no doubt I can pull 20+ miles that 1st day - including getting to the summit of Whitney. I've done big miles many times. What I don't know and have doubts about is being able to follow it up with multiple 20+ mile days.
I know every bit of the trail like the back of my hand all the way to the turn to Kersarge (though from the other direction). I've done it a bunch of times. There is a chunk of trail that I've never seen from there to the approach to Pinchot Pass. Then I'm on semi familar ground again as I head towards the middle fork. After that it's all new until I get deep into Yosemite on that last day.
Last year I went from OV to KC and back in a day - but I couldn't hike the next day. Walking was a challenge. I still have pain in one foot from my KC loop last year.
I don't fear big miles - I just really, really worry about big miles on top of big miles.
I guess I need to get out for a practice run this year and see how it goes. If I fall flat on my face I'll know I need to scale back. I just wanna give it a try though.
Heck, at ten days I'll only be a week shy of the JMT record.