Welcome to the forum! And have fun with the CPO search!
I'm not in anything like your climate in Denver, but we do get some very cold spells here in the Midwest (about 10 days in a row with single digit or below zero high temps in Jan). I would think you would definitely want to look at a Dual motor S, for dealing with the conditions you will regularly experience out there.
However, do be prepared, you will absolutely see a decrease in the usable mileage when the temps are cold (below 30-35F). There are plenty of cold weather discussion threads on here, search for them and do lots of research - but I have experienced as much as 40-50% loss in range when the temps are extreme cold (single digits)...throw in drastic elevation changes and you could see more.
This is not to say owning an S (or X) isn't possible (and super fun) in colder climates, many people do - it juts takes more planning and an awareness of your driving style when you are dealing with inclement weather/temps.
Do some looking around for the cold weather threads here, you will learn a lot, and hopefully that will help with your CPO search.