Spartan,
You will have a great time. Take lots of photos and share them
For 3 years in the early 1990's, we bow hunted CO in the Flat Tops Wilderness, near Orno Peak.
We self guided and packed in ( on foot) and hunted out of a spike camp, to get away from the walk in day hunters.
Excellent, comfortable footwear was required. It seemed like we were always walking up or down, seldom any flat areas.
Packing in enough water was impossible, so we carried a high quality water filter and topped off our water bottles near every stream.
Drink more than you think you need as the altitude and dry mountain air will leave you dehydrated before you realize it.
We hunted around 10,000 ft and the thin air really taxed us.
I found doing leg squats (low weight, lots of reps) helped me get ready for hiking in the mountains.
Your guide should have a list of the things you will need to bring, and a list of what not to bring
Practice shooting while your heart is pounding, you are short of breath, stressed, and from odd positions.
That bull will appear when you least expect it. Murphy's law works overtime in the mountains
A poor hit is a poor hit, even with a .300 Win Mag.
Know your limitations.
Have fun and good luck!