You "can" open carry anywhere provided that it is not in a school zone, bar, or government building. But you may very well be detained or arrested for doing so. Kind of an oxymoron. Can but cant.
I open carry when outside on my property, occasionally when I go to local stores. I have been detained, threatened with arrest, and released before.
I would encourage you to excersize your right to carry a firearm for self protection but you should be aware of potential problems. Wisconsin is not a bad place to live other than relations to firearms laws and taxes.