There are very few units open for late muzzleloader where cows are legal. There are a few but they mostly are made up of private land with difficult access and in some cases very few elk in the unit, except in very specific areas, which without a lot of pre-season scouting you will not be able to find, and even if you did chances are the elk would be on private land where hunting is not allowed. The one I would probably recommend would be the Lincoln unit. There are a few elk in there and much of the unit is Weyerhaeuser or State, so you've got good access but good luck finding the elk. If I knew where they were I'd be hunting there myself. Good luck. If I were you I'd look at this season more as just pre-season scouting for next year.