While you will be on the very Southern Border of the "Wisconsin Food Belt", I am sure you will have the chance to enjoy some local favorites.
A side dish with sandwiches that is spreading even into this area, but is based up there is the Cheese Curd…battered or breaded and fried. served like french fries in a small pouch or box.
Walleye is the fish of choice in most fried fish sandwiches. Tasty and a bit different from the Catfish I am used to. Dollar sized Perch Filets are another fish dish we found and enjoyed in Wisconsin. Served broiled or grilled in butter. About 6 or so to an order, they make a nice entree.
Lots of German-American style food in that area, reflecting the heritage of many opf the communities around the area.
The Illinois Rail Museum is in Uniontown near Rockford. If you have any interest in Railroading , it is an inexpensive place to spend 1/2 a day.
We have family a bit further north (Baraboo,WI) so we seldom stop in the Rockford area itself. I hope other members will give you the names of some specific food stops.