While I don't have a Montana, the construction of my Cougar should be similar. With a little foresight and preparedness, wintering is manageable, here's some links to the upgrades that I made to get through this past winter in New Hampshire
http://www.keystoneforums.com/forums...ad.php?t=27186
http://www.keystoneforums.com/forums...ad.php?t=26660