Not sure about your climate. Does it need to be insulated or not? Can you use all year without insulation?

Hello , I am a fellow Montanan! :) I think bunkhouses are great, a western version of a guesthouse. What a great get away. I see plywood walls treated with linseed oil or some kind of low luster polyurethane. Something to bring out any hidden wood grains. I think there is charm in stoking the wood stove or throwing a log on the fire. Heck I would even settle for firing up the ole space heater on a frosty day. I think good windows and slider will help make it more cozy. Anybody can have drywall. Go for character. Summers with every thing flung open for the cool mornings, and Winters with everything sewed up tight! Couldn't be better.

Angel: I have insulation in the walls already. Still in good shape too!