Gabby is five months old and has been on the trails and learning how climb on the rocks. The hardest thing for her was to cross over a crack between two rocks that was very deep, her brain would tell her no matter how shallow it was, a cliff is in front of her. I showed her a few times and made a game of it and now she has no problem crossing wide areas that are fifty feet deep.
I think like you, the dog must train there muscles and lungs for this. We are at altitude were we live but when I go fishing with her we are 9,000 to 10,000 feet this is a big change for any animal. The 25 foot leader I have on her gives her the ability to get into trouble but allows me to help get her out with the help of a harness.
In the canyon that is in the back yard we have rattle snakes so I am very carefull of that also and don't forget IT IS TICK SEASON FOR ARE AREAS. Check all of both your body's.