It’s been a while since you posted this question.
I’ve taken many backcountry hikes in the Tuscan hills of Italy. This actually where my permanent home is.
I’ve found that my weakness was being able to control my speed and balance when going down hills that are pretty pebbly. For me that has been exhilarating but a little frightening as I felt I was going to fall. It impressed upon me the importance of eccentric training of the musculature of my lower body.
Fairly recently, the elevators in my building were not working and I had to walk down from the 61st floor. The next day I had muscular soreness like I had never experienced. Likely related to eccentric strength weakness.
If there was any one thing I would say you prepare for it would be balance and eccentric strength.
I hope this is helpful to you.