I went through this last year and decided on being able to run 6 miles in an hour as an indication that I was in shape for hunting. I do a decent amount of manual labor around the house and play a little bit of farmer so I don't feel that I need to do much weightlifting or anything like that.
I really felt like I was really in good shape and hunted hard for 5 days when I would have probably worn myself out much sooner if I hadn't been in that good of shape. On the 4th day I was 7 miles in from the trailhead at 10,250' elevation in 6" of snow on my way back down the mountain at 9:00 AM when I encountered a guy on horseback on his way up the mountain. I think all the working out was worth it just to see the look on his face.
After seeing how much more enjoyable my season turned out last year I decided to take it up a notch this year and be in good enough shape to run a half marathon in 2 hours. I didn't realize how much more difficult that would be than running 6 miles in an hour as not only is it more than twice as far, but it is also at a full minute per mile faster over the entire distance. It took some work but I already pulled it off at the end of April, running 13.1 miles in 1 hour 55 minutes and 43 seconds. I'm running about 25 miles per week now just staying in shape over the summer and might push the mileage up a bit once it starts cooling down.
One important thing I've learned is that you need to do the vast majority of your training at a very easy pace. You shouldn't be sucking air and struggling on a training jog, you should feel like you could carry on an easy conversation with someone if they were running with you. Most of my training runs right now are in the 11 minute per mile range, but that slower pace really builds your aerobic engine and thats what you need for hunting anyway.
It is probably a good idea to do some cross training to build and strengthen your legs with stairs or an elliptical on full resistance as well to help on the hills.
Also one of the best tips is to either get to altitude that you are going to hunt a few days before the hunt or just take it easier the first couple days of your hunt while you aclimatize. If you get to 8,000' elevation from 1,600' elevation and start going as hard as you can that same day you are going to wear yourself out no matter what kind of shape you are in.
Probably more info than you wanted but that's my thoughts on the subject.
FWIW, Nathan
