johnny - I hate to put a damper on your dream. But I just came back from an elk hunt in early November. I'm 54. Me, my friend and our guide walked 5 - 15 miles a day. Up and down mtns. Wake up at 3:15 and not get back till about 8:00 at night. You spend a lot of time glassing then walking and glassing some more. At sunset you could be 3 ridges over from your vehicle. And that's the easy part. If you're LUCKY enough to connect on a bull. You have to take out all edible meat. Then the cape/antlers. This will takeusaually two trips with 3 guys. Strong legs, back and heart is definately required.
My recommendation, before you even book a hunt, tell the outfitter your health condition and what your chances of success are - and ask him for references. Ask him if he uses horses or ATV to get game out. Good Luck and wish you well.