I have never hunted in the mountains or for elk

[Devil Diver Down]

Has anyone mentioned conditioning yet? If not, let me be the first.

All good advice on here - especially those urging you to have fun and manage your expectations your first trip. Also, no matter whether you're car camping or backpacking, you should be prepared for a variety of weather conditions. On my 2 September bow hunts (more like bow hikes for me) to CO, I've had stifling heat, snow and plenty of rain - sometimes on back-to-back days. It can turn very nasty, very quickly in the Rockies.

Have a great hunt and report back with pix and a story.

 

[Tradewind]

Western outfitters will tell you hunters from the east have the same two problems. They are not in shape and they can't shoot at western distances.
As everyone has pointed out, the better shape you are in the easier it will be. But there are a couple components to it tht I have found. If you can run a 25 min 5k you will survive the hunt without too much trouble. But what you will notice after the first day is that your glutes and hips will get over worked. especially if you are carrying a pack of any weight. I would make sure you do a lot of stairs. If I only had time for one exercise each day it would be walking flights of stairs. And don't over do it. Spend a couple of months getting a base in; to the point where you can climb 10 to 12 flights of stairs a couple times per day without a problem and your knees and glutes handle it without complaint.
Then about june start adding some weight, say 20 lbs. Increase it to 50 lbs in august - assuming you have been diligent.
If the knees are sore take it easy that day, do the elliptical or wait until later in the day when things loosen up. Also, if you are over 40 make sure you stretch a little each day. Each day sit on the bottom stair with your feet on the floor and slowly work your legs into a deep knee bend and hold it to where your calves are hard against your hamstrings and hold it there. Then stretch the groin, hamstrings and quads. How far you get stretch isn't really the issue, only that you stretch them. When you are out on your hunt do the same stretches each morning before you head out. The trick is to have the muscles limber and toned enough to handle the off balance tweaks that you always get but cannot train for while hunting.
For the shooting, Cushman was right. Practice at odd angles. Put brush in the way that you need to guess the arc of your arrow will need to take to get through there. Go sprint a 1/4 mile then pick up your bow at an unknown distance. While you're huffing and puffing practice getting a quick range and fire.
Everyone says have fun. Right. Life's a beach. For me the fun comes when I am out there and I don't think twice about heading up the next ridge or over the far drainage because I'm too tired. Nothing worse than getting half way thru the first day of a week long hunt and thinking I wish I would have trained more.
Yes, the boots are important. Make sure you wear the pair you are going to hunt in for a full day with weight on your back. Get tired and sweaty in them to know where the hot spots are going to potentially show up at and where the support will be and not be in them.
Good luck