I've been scanning and cleaning up a 200 page book that is a collection of "Travel Mats" that were printed during the Route 66 heyday [1].
Each focuses on a specific highway and list motel and diner stops.
[1] Example: https://external-content.duckduckgo.com/iu/?u=https%3A%2F%2F...
I should have it done and posted to archive.org this Fall sometime.