Hi dirt, I really know nothing of 680 other than being near Great Falls. I did look at some of my maps and road access appears to be no problem and seems to be a lot of flat land and state land available to hunt. If you plan on hunting 680 I suggest in calling the great falls BLM office and obtain a BLM map of the unit as these are most helpful in identifing land ownership, topo and road access. All or most of those hunting units in 400, 500, 600, and 700 have an abundance of unlimited tags avaliable for elk, deer and antelope. I'm hunting just to the east of unit 680. I'll be in units 410 and 700 where the mussleshell river and missiour river comes together. With a 900 antelope tag you can hunt in hunting units begining with 3,4,5,6,or7 and shoot up to 2 goats. As far as deer goes, its as many tags as you want to buy.
Why 680? Just curious why that one stands out to you? Good Luck, Bobby