Take your time. Breath deeply. Altitude and attitude are different.
Be in good physical condition before you get there. During the race....be patient but persistent. The goal is to finish standing strong and proud.
If necessary, slow down, swim on your back and breast stroke. Bicycle in a steady pace and if necessary slow down or even stop for a few moments.
During the run if stressed or strained ...slow to a jog or just walk but keep going.
Water....Gels....food bars....spaced along the way will make a difference.
I am 71 and have done several TRI's in recent years and this year I will TRI to average one per month.
JUST BE HAPPY TO BE THERE AND....KEEP ON KEEPING ON TRI'ING.
I lived in Boulder in the 90's and loved it.
Gale Bernhardt (an Active.com Expert) wrote a long article on this topic. Here is the link to Part I, click the link at the end for Part II. This article gets very technical, lots of scientific terminology.
The city of Boulder's elevation is 5,400 feet. Colorado has 100 peaks that exceed 13,120 feet (4,000 meters). Boulder is a very bike friendly community, here is a link to their web site:
I would spend the first two days getting acclimated to Boulder's elevation. I would spend the next three days training at higher elevations, and the evenings at Boulder's relatively lower elevation. Complete rest the day before your competition. You should be fine. Here is another link, I recommend the Boulder to Ward route.
I too am doing this race!! I have plans for training in Flagstaff every weekend I can during the next 8 weeks...not that that would make me stronger, but perhaps it would get me used to gasping for air. Do you have a place near you with higher elevations? I have read up on this a little bit....here is some of what I have heard: Use iron supplements as that will assist in the Oxygen carrying in the blood, stick to high carbs and up your fluids. Some people also suggested chlorophyll (for similiar reasons as using the Iron) in addition to eating plenty of greens such as wheat grass/barley. During the race, increase fluids as well since with every breath you exhale, you exhale moisture. They also suggest that if you feel winded or like you are greatly struggling, just relax and slow your pace down until you can regulate your breathing.
We are heading up there a couple days ahead...I would suggest just chilling out and adjusting very slowly if you can. Hope you have a good race! Im praying I don't struggle too badly either