Hi @TERRI5 ,
I have limited experience in Colorado specifically, but have lots of hiking miles under my boots. Personally, I prefer a boot that extends above the ankle. It provides additional support, protects against abrasion, as well as water and dirt intrusion. My current favorite for heavy/winter usage is a boot from Under Armour, but which is sadly discontinued now. Those UA boots have over 500 miles logged, and are starting to show their wear, so I will be looking for replacements soon. In the summer I have a pair of Merrell Capra Bolts, which are also about to be replaced.
Now, that having been said, everyone has their own personal preferences regarding factors such as weight, waterproof or not, low or high ankle coverage, tread pattern/traction, etc.
The most important thing that I can recommend is fit. Find something that fits well under the conditions you will experience, like steep ascents and descents. A shoe or boot that seems fine on level ground may allow your foot to slide too much, leading to hot spots and blisters; or may not allow enough freedom of movement which could result in damage to your toes and nails.
I also recommend wool socks with good cushioning. I also like using liner socks as well. They help to minimize sweat and keeps your feet comfortable. Make sure to match your shoe/boot size to the thickness of socks you'll be wearing. Gaiters may also be a good accessory for you to consider.
Good luck, and have a great time on your trip!
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