Just remember that fall/winter flocks will most likely not respond to your typical turkey calling. They are much more interested in food and water so look for that. Historically on public land, our turkeys tend to move onto private property as it gets colder, especially on cattle farms where live stock feed is out. I think in the 20 years of chasing our local birds, I have ran into public land winter birds only a few times but that doesn't mean you wont find them on public land. Check for tracks near water holes to see if its being used, winter birds wont venture too far away from cover, food, and water so if you see tracks near any of that you'll have a good chance of finding turkeys.
Good luck!