I, too, loved the old store lunch counters. My favorite was probably those in "dime stores." Favorite order there was a BBQ sandwich with soda.
There was a cafeteria in downtown St. Louis named the Black Cat that served awesome roast beef and cherry pie. It was near the old GM manufacturing plant. We ate lunch there each time Mom and Dad drove down from IL to pick up a new car for the dealership owned by my uncle.
The Sip 'n Bite in downtown Dwight, IL served sandwiches and ice cream in an old soda fountain atmosphere. Used to walk there with Mom and relish nearly everything they served. It's gone now, of course.
Favorite road food when a kid was hot roast beef sandwich with mashed potatoes and gravy. Ate this in many, many mom 'n pop establishments on 66, 36, and 100....Bliss