Maybe there would be some older drive-ins or diners that you might get lucky at. Here's an example in Winona MN, which is the same town that has a write-up in the Roadfood Restaurant column, Bloedow's Bakery.
If anyone local should see this, I have to warn you the Lakeview's food is pretty mediocre, they seem pretty indifferent about it. But they are usually busy. Maybe in part it's because the root beer is good, and it's just the idea of the place. Plus we have a lot of college kids here, and what do they know?? (just kidding!)
Scroll down to Specialty Sandwiches. They say it's the original!
They also have something else I've never seen anywhere. They call it a "shrimp patti", and it is actual cut up pieces of shrimp packed together with some kind of binder into a patty and deep fried. Different than on the east coast, where the shrimp is in individual pieces. This is all in one piece, like some fast food deep fried fish sandwich. It's actually not bad. Expensive for what you get.
But the place has been around since 1938, so good or bad, they're Roadfood! http://www.lakeviewdriveinn.com/menu.html