There's a good Mod Squad contingent in Wisconsin and surrounding areas.
But that's more players than fields. We'll have to get together and play sometime.
A lot of places have a field or two pretty close, and then we start looking at road trips to get to other fields. If you're not opposed to making a trip, Stalker by the Dells is a great field. Apocalypse by Portage is great, too. There's a couple smaller fields in the middle of the state that I've been to but haven't yet personally played. Outdoor Adventures in Fremont is another long-standing field.