You will have a blast. I have been a half dozen times - my college room mates were Kevin Lindville and Mike Whitman - they ran a cosworth pro rally car up there for several years.
Just a few FYI's: Even living in Colorado, when you are at the top you will not be able to move very fast without losing your breath very quickly. Drink lots of water and take it easy. Aslo, I cant tell you the amount of times it was sleeting/just shy of snowing even though it was summer down in town.
If you decide to go to the top to watch (or even as high as Devils) plan for a long day with food/drink etc. You will have to not only wait until the race is completed to leave, but you have to wait until the race cars (including the big trucks) are driven back down as well. I would reccommend getting there the night before - or VERY early the day of.
Again, if you camp - prepare for all sorts of different weather - there is a good chance that there will be a fire ban.
You really will have a great time!!!!