Dude, rent, rent, rent. Rent some 2-up 4 stroke ski-doos, or whatever the local shops in Bozeman have. Ride them for a weekend and then decide what you want to buy.
You'll learn soooo much, just by renting sleds for a weekend. You may find that it's not at all how you dreamed it would be or you may realize you want more of a performance sled. Renting first will be your cheapest option, by far.
Oh yeah i have one rented for a forest service cabin trip soon. Bad news is its 45 degrees today wtf? So when it snows,again ill go rent a couple different kinds and see whats up. Iam just bad that way. I allways jump right in. Good advice