Observations...
You are going 5 miles per day. This is more than enough exercise. Your first day is 6 miles, +3,600' and you have all day to do it. Hike out to Lone Pine Lake...have a meal, lounge around and take a nap. This is the hardest part of your trip.
The first part of your second day is 5 miles, +2,800' or so with a 15# pack, whose weight is constantly decreasing and returning to Trail Camp. The hardest part of this day is going Lower Trail Crest to Trail Crest. The adrenaline is gone and this 1/4 mile stretch seems to go on forever. From Trail Crest to Whitney Portal is all downhill...a controlled fall. I never have a problem descending.
Driving home at the end of this can present a problem...if you are tired, stop and nap for 15 minutes.
Bears ain't a problem at Trail Camp...marmot are. Do not leave food laying around or it will gonzo. I lost all my breakfast foods once when I forgot to put them back in my canister.
