I'm in my early 70's. My regimen is similar to part of yours. I take an 81 grain aspirin tablet every day in addition to a multivitamin and saw palmetto (BPH is a separate issue from altitude acclimation). I also get at least an hour of aerobic exercise six days per week. That is pretty much it for my regimen.

I recently hiked the JMT with no ill effects from altitude, even on the first few days of the hike. In my opinion, staying in shape is much easier than getting in shape for the older hiker.