RE: London, ON to Indiana--good stops on the way?
I am assuming that you will be following Interstate 94 across Michigan and turning south into Indiana on Interstate 69. I am going to suggest Cornwell's Turkeyville USA near Marshall, Michigan.
They serve no beef, no pork, no fish, no chicken - only turkey. This family business started over a hundred years ago as a farm, and at one point they began raising turkeys, dressing and selling the turkeys to local residents to be cooked for their Thanksgiving dinners. Then they started selling turkey sandwiches from a small roadside stand. This has become a large cafeteria style restaurant, with selections that range from the Sloppy Tom sandwich to a full turkey dinner with all the trimmings, and a ice cream shop in an adjoining part of the building. There is also a dinner theater and an extensive craft and souvenir shop in the back part of the building. As the business has evolved over the years, the only thing that has remained constant is the turkey.
The restaurant is located 6 miles north of Marshall - the best way to find it is to travel north on Interstate 69 from Interstate 94 to exit 42, the N Drive North exit. Turn west at the stop sign onto N Drive North - Turkeyville is a mile ahead at the intersection of N Drive North and 15-1/2 Mile Road.
Another option is Clay's Family Restaurant, which can be found just south of the Michigan-Indiana border. Take the first exit off Interstate 69 in Indiana, turn right at the end of the exit ramp, then turn right again at the four-way stop. Clay's is about 2 miles ahead on the left.