I've just finished this and really enjoyed it. Dh had read it first. We're both avid hikers so that aspect appealed.
Their circumstances were very rough. I know they made mistakes but reading about how they overcame them was fascinating.
What I did struggle with was the fact so many people commented on them being old? Me and dh have done a few long distance walks and have seen all ages. Dh is in his 60s and I'm early 50s. Never has our age been mentioned.
So I do feel the story has been embroidered somewhat. The author doesn't look ancient