I'm writing story-generating software. One specific story involves a farmer with a variable name. I'll use "John" as an example. For a "folksy" or "old-timey" or "child-targeted" sound to the story, I always refer to the character as "Farmer John" instead of just "John."
Starting sentences, it's clear that the "F" in "Farmer John" is capitalized -- but I'm unclear whether the "F" in "Farmer John" should be capitalized mid-sentence as well.
E.g. which of these is correct, and why?
Martha sees Farmer John building a barn.
Martha sees farmer John building a barn.
My doubt is because in the context that I'm using "Farmer John", it feels as though the entirety of "Farmer John" is a name/pronoun, therefore both words deserving capitalization -- but I can't claim anything other than a gut feeling to legitimize that.