Where I have elk hunted the past couple times, to get to where we hunt it's about 2000' elevation gain over 1 mile, so average 45% slope. There are short stretches where it is much worse than that, it's borderline rock climbing. And there are sheer cliffs in either direction if you take a wrong turn. We did that every morning we hunted that area and it takes us (including my 50-some year old dad) a little over an hour to climb, and we are in good athletic shape but certainly aren't gym rats or supermarathon athletes. We take it slow and take a couple short breaks, the worst thing you can do is to try to go too fast, then you blow all your stamina.
Is it fun...hell no. But there are elk up there. Does it cut down on the amount of other hunters you see up there? I think it absolutely does as I have seen one boot track and scant other evidence of other guys. That's why we do it.
The important part, safety wise, is that you have to pick your routes carefully, and be a good enough navigator to ensure you don't get yourself in a pinch where you're cliffed off on all sides. It's particularly butthole clenching in the dark, which we didn't even attempt until we did it a few times in the daylight. Going down is much more dangerous than going up, go slow, zig-zag or switchback, and when (not if) you fall, be damn sure that you keep your center of gravity such that you fall backwards and slide on your ass, not go forward ass over elbows.
