Training for a mountain hunt where there are no mountains

[Fordguy]

Find sand. Even better, find sand dunes or sand hills and if legal, train by hiking up and down them with your pack. Jog through them if possible too.
I know we aren't horses, but when I used to enter endurance rides with my horses, their conditioning improved dramatically when I worked them out on sand.

 

[EJDXT21]

When my kids were younger we purchased a trampoline. I ended up spending a lot of time bouncing them around that first summer. That fall when I went on a back pack hunt I was amazed how easy carrying my pack felt. I now incorporate trampoline time in my workouts. If you go hard it really works your heart and lungs as well as core strength/legs. Excellent all around workout.

I agree with this 100%. I actually refused to jump on the trampoline with my kids after the first time cuz my body was so sore lol!