I would double check the routes before you go. I-70 over the mountains from Denver to Grand Junction requires you have AWD/4WD, snow tires, or carry chains after September. All tires require 3/16th tread depth.
If you have no other complaints about your car, and you have somewhere to store them in the off season, I would get a set of snow tires on separate rims. DH had a set to commute with for our compact car and it made a world of difference.
I love my Subaru and hate it at the same time. So be careful buying one. Admittedly I beat the crap out of mine and used it to tow about 70% of the time. But in 50k miles I've replaced more in parts than the 8k I paid for the car initially. That was with deals on labor, getting the head gaskets under warranty, and it now needs a catalytic converter! If you did want to buy a Subaru get it in PA, not in Utah. Subaru's around here are in high demand and priced accordingly.