I live in Wisconsin also. Some of the best places to hunt are the yards, front and back, of the older homes in the town right where you live. I have never failed to get less than a handful of silver from any of them. They usually have several rings also, and some of them can be nice. Next best place is old beaches.
Visit your local historical society to find out where the old bridges, buildings, mills, etc. were located.
I found post cards on Ebay of a few different old beaches in Wisconsin, copied the picture of the item, went to the town and asked around to find out where the location was. I found one that way in Black River Falls. Haven't been able to hunt the site yet, but maybe next year. Buddies found rings appraised at 5 and 8 thousand$ at an old beach site once.
Ever throw a penny off a bridge into the water? That's been going on since bridges were built, and just where I found an 1848 large cent, at once inch depth, on the footpath along the river almost directly under the bridge.
Where does the city dump the snow they remove from streets and parking lots? Once it melts, you won't need a detector, just pick up all the coins. I did that in Eau Claire once and found a license plate from a police car in the pile.
You're only limited by the ideas you come up with. Think old, learn old, learn your city history, talk to old people about their youth, it's about all they remember and want to talk about it seems. check old maps of your city, get satellite pics and check them.
A guy I know was fishing along the Red Cedar River a few years ago, just sitting and leaning against a tree, watching his line. His heel kept catching on something stuck in the ground, so he dug it out. It was an ancient copper knife and sheath, with strange symbols/ writing on it. It is thought to be Phoenician. With a little (re) searching, you'll find more places to hunt than you will find time to hunt them.
I happened to visit an old university in Ashland one day and saw that they were tearing up a stretch of old sidewalk next to the driveway. I rolled the window down and drove very slow while looking at the turf and dirt alongside, and found 3 Indianhead cents. The hard part about it was getting out of the truck to pick them out of the dirt. Rough eh? Imagine what I'd have found if I had brought my md along that day, (shame on me for not).
i wish i lived down south where you could find war relics or live in Florida for beach hunting after hurricanes for them Spanish coins. 
Guess I'll take the cold weather and the fresh water beaches. Where u located ? I'm out of delafield. If i find something credible I'll send u a message.
