Ed, congrats on continuing hiking at 70! (I'm only a few years behind.)
It sounds like you are more susceptible to AMS than average, so you should really work to address that. I'm like you when hiking at altitude--just don't have much appetite and never really feel thirsty. So I make a conscious effort to drink -- at least a pint every hour, and maybe even more. Adding electrolyte tablets to a drink makes it way more appetizing. (Check out those Nuun tablets.) Carry snacks that you really like to eat, and try to eat at least as much as a granola bar every hour.
When you go this year, spend one and maybe two nights as high as possible -- my favorite is Horseshoe Meadows. If you could do that the first night, then maybe head up to the White Mountain area for another night, (possibly hiking White Mountain on day 2 or 3 of your trip), you would probably be acclimated well enough to enjoy your trip to Whitney.
Assuming you are retired, you don't have to be on any sort of time schedule, so take lots of time acclimating. That will help make your trip a success.
Oh, one more thing: Since you are so susceptible, do get a prescription for Diamox (acetazolamide), and start taking it on those days and nights you are acclimating. (Just take a dose or two at home to make sure you don't have any bad side effects.) Don't take more than 125 mg twice a day. Higher dosages are for glaucoma patients, and that causes worse side effects--buzzing/tingling finger tips is one.
