When asking google about the original, classic King Ranch Casserole this site appeared on Screen.
http://www.npr.org/2014/01/16/262527082/the-taste-of-south-texas-in-a-9x13-dish
There is included a tale as to where and what King Ranch.
Thanks. I wonder if the original used canned soups...but I can’t seem to figure out what the original actually was ;-)
In fact this site has a number of found recipes, different origins, different dishes.
NPR - FOUND RECIPES
http://www.npr.org/series/175306271/found-recipes