Actor Allusion: In a rather subtle example, while visiting Oliver and Lisa, Oliver's mother watches television, while other townsfolk join her (against her wishes). They watch an old Gene Autry movie, which Mr. Haney seems to really enjoy (except for him always getting the girl); Pat Buttram was also Autry's regular sidekick on The Gene Autry Show.
Recycled Set: It's clear this show only has one painted flat that's used for scenery, no matter what part of Hooterville you're in, let alone, what part of the Douglas far you're on. Pay close attention, you can see the exact same rolling hills and distant mountain in the background almost everywhere.
Pat Buttrum (Mr. Haney) famously remarked "CBS canceled everything with a tree in it!"
Unintentional Period Piece: Averted. The show pretty much relied on the stigma that modern people (well, modern for The Sixties) were flocking more to city life, and leaving the country and farming behind, with Oliver being the biggest exception. Other than that, Mr. Drucker directly mentions the year 1966 in one second season (1966-67) episode.
Write Who You Know: Pat Buttram based his performance of Mr. Haney on Colonel Tom Parker, Elvis Presley's manager, who he had met several years before when Parker worked as a carnival barker.