I would rely on the guys in your group that have been before. Not just for the information on the area, but for what you need to take as well.
Under Armour works just like the other base layers that are made of polyester and spandex. NO better, no worse. Microfiber anything (used to be called polyester) but now a whole generation of younger folks will swear that UA is better than having an extra thumb. But the cheaper versions will do the exact same thing. My son says the compression of UA helps. To which I say Okay, buy a size too small of the cheaper version. Same thing. (Stepping down from soap box.....)
Layers is best in the West. Could be hot and cold and all in the same day even. If you are cold natured, nothing wrong with nice parka and bibs. But being able to take them off during the day is essential and then you might have to tote them around. You will figure it out real quick. But since you are returning to cabin at night you can adjust daily. No biggie...
Good luck.