There is some realistic advice in this thread. It sounds like you have done a realistic assessment of where you are physically. Seriously, if you intend to hunt CO high country this fall, you would be well served to start an exercise program now to get you in better condition. You don't have to be Superman, but any improvement in conditioning between now and fall will help. You are not that old, lots of people past 60 still chase elk. But like they say, hunt smarter. It has been too long since I paid attention to CO units, so I can't guess where to put your points, but here is some advice otherwise.
The truth is if you want a good bull, a guide is the best answer, and if you want to get back into wilderness type hunting, horses are the way. It did not sound like you have buddies to take along, so since you don't think you can handle an elk on the ground alone, you are really talking yourself into using a guide. 16 points is a lot of waiting. Why blow them on a low probability hunt? Or one that may turn into a real ordeal?
Having hunted several places in CO and other places in different states over the years, I can say it takes several seasons to get to know an area, learn the elk trails, their movement patterns, favorite cover, and then there are places where they are there during migration and very scarce at other times. Every year is different. One year opening day is 80 degrees, the next you are into the second blizzard of the fall. Since you are not local, you don't have the time to learn all this. You have already seen this in area 80 on your "camping trips". Elk are not just big white tailed deer - they act way different. They are not scattered evenly across the landscape. You would need to learn elk behavior, habitat, timing, patterns, etc. in a few short days. That is where a guide will earn his pay. Get a guy with good references, and trust his knowledge - that is his business. The rest of us weekend hunters, or even those of us who take a week or two at a time, have spent a lot of that walking empty country. Our advantage is we live around elk, observe them year round, and we may have time to go back for another try during a season. CO seasons are short and unforgiving. Increase your odds for success by using someone else's legwork and knowledge.
And one last thought, if you have the time, arrive a couple days preseason to get accustomed to the altitude. It takes a few days, and altitude sickness is nothing to take lightly - it can kill a person. Being in good or not good condition does not mean you will get it or not. The best preparation is a little time at higher elevation. You may have already experienced this. But if you do go with a guide, and you get back in with horses, you most likely will also be going up. Check with your guide to learn the local conditions and altitude. Increase your chances for a good trip and do some preparation.
