It may be a little north of your path, but Shipshewana IN, about 35 miles east of South Bend, is a big Amish Center, complete with Amish grocery stores and restaurants, and a lot of buggies on the highways.
Here’s what Wiki says:
Shipshewana is a town in Newbury Township, LaGrange County, Indiana, United States. The population was 658 at the 2010 census. It is the location of the Menno-Hof Amish & Mennonite Museum, which showcases the history of the Amish and Mennonite peoples. Wikipedia
Several places in Missouri too.
Not too far from there is a town called Nappanee, which has a place called Amish Acres complete with a theater believe it or not. First time I ever ate peanut butter pie.
Indiana also has offshoots of Amish they call “jerked over Amish” - Mennonites and Dunkards.