Halfway between Minneapolis and Milwaukee, eh? Smells like Madison to me. Okay, I guess that's more than halfway, favoring Milwaukee, but it's still your best bet for good eats in that general area. Start with this thread for ideas: http://www.roadfood.com/F...71092&high=madison
Then try a search on the site. There's a place called Monk's in the Wisconsin Dells that hits closer to your geographic goal.
BTW, the actual midpoint would put you in Tomah, Wisconsin, which I've found to be a disappointment in terms of Roadfood. Plenty of fast food chains off the highway, and a poor excuse for a Wisconsin Supper Club (The TeePee) in town. You're much better off driving to Madison or Monk's.
Have a safe trip!
Wisconsin Dells, WI