I'm not sure how familiar you are with the search engine on this website. Where it says "enter recipe or keyword" next to search, you will want to type in "high altitude baking". When nothing will probably come up, then go over to the left where it says "community" and click on that. The first you come up with is for the TOH only search (magazines) and when you click on community, then you are getting access to what has been discussed on this BB.
With that being said, I do know you can get excellent information from your CO Extension office.
I live in the Salt Lake area and have problems too, but not sure as serious as you. In an older BH&G cookbook (for 5,000 ft) they say these are the 3 changes you can make.
#1 is your liquid - add for each cup - 2 to 4 TB
#2 is your baking powder - decrease for each tsp - 1/8 to 1/4 tsp
#3 is sugar - decrease for each cup - 0 to 2 TB
I have read quite a bit on the topic and most of the articles say to only try 1 change at a time and always begin with the smallest number. What I read mostly is to begin with the change in the baking power first and if that doesn't help add 1 more change.
On cakes, I do know that I have much better luck with baking a cake in 2 smaller pans rather than a 9x13. I do the same for quick breads - I don't bother with a 9x5x3 - I use those small ones (can't think of the dimensions right now).
Yeast breads don't seem to be bothered by the altitude, at least for what I've made. Your best bet is the Extension Service.