John I'd suggest a walk in cooler somewhere in your shop area, a space where you could either hang a beef or big game animals then a butcher shop area with a chest freezer or two close by since I've got a feeling you'll be doing something hunting as well.
A rail system into the cooler would be helpful also for dealing with 1/4's of beef or what ever a walk in freezer would be great also while I'm at it a smoker somewhere close by would be a great addition so you can make sausage, hams, jerky or ????
A area for a old ringer washing machine for muddy critters is critical with a rack or some sort to dry the fur, that when not in use will or could be moved out of the way.
A generator is another thing I'd add to the mix just because this is Montana and power outages are rare but still possible solar panels and a few batteries could be added also in time.
There ya go a little something to think about in your spare time ha ha
Allan

Wow jeff some trappers we are! all this chat about a fur shed and your the first to mention a dehumidifier!