Hey Blake,
I have some experience with hunting Montana on state and other public land. Best thing I can tell you to do is go to the hunt planner on the fish and game site.
http://fwp.mt.gov/hunting/planahunt/default.aspx Figure out the zone and species you want to hunt. Then zoom in closer so you can see the exact area you want to go. Any area in Purple or Yellow you can hunt. They are either BLM or State lands. You can also usually hunt the green which are federal lands. I will warn you to look closely as a random fence line could mean the difference between public land and another persons private land. As you zoom in you will see what I am talking about. You can also buy a map for the regions from the fish and game department. Its either 10 or 20 bucks, but good to have in the truck when you can't have a computer on your lap. Oh and one more thing, some of the BLM and other private lands require written permission even though they may be on the map. If thats the case it has to be posted. You simply then find the landowner (which should be on the posting) then they write you up on an official Montana document you put in your car window. Hope this helps. Let me know if you have more questions.