I know from your previous posts that you very much partake in musculoskeletal exercises, including lifting heavy. And I agree about the Ass-to-Grass squats for conditioning connective tissues.
As for the Appalachians, they are generally a very rugged mountain range to hike, much steeper than much of the Cascades, despite the Cascades towering over the dying Appalachians -- dying because it's one of the oldest mountain ranges in the world at just over a billion years old, which is why they're no longer tens of thousands of feet in height. However, they are very steep and rugged.
And that steep/rugged terrain is why the Appalachian Trail is a major destination and a
Holy Grail for speed hikers attempting a Fastest Known Time (FKT) hike.
For people not use to the conditions presented by the Appalachians, it's best for them to not worry so much about cardio conditioning, rather work on the musculoskeletal system, especially connective tissues, which when injured can take a very long time to recover. Cardio will come naturally, you just start slower, but the physical body needs more of an introduction, not even walking down stairs provides a good enough conditioning for the steep grades of the Appalachians. Walking down a gentle sloop is nothing compared to the steep declines found on the AT
BTW, I also totally agree to stay away from NSAIDs -- I stay far far away from all types, if my knees are sore that's my body communicating with me, listen to it, don't shut it up.
And to see how this still applies to cycling.
https://t100triathlon.com/articles/r...core%20control.