The Brady Bunch movies had a gag about a classic TV shared universe. As it turns out, there already was a very prominent one all under the producer Paul Henning.
First out of the gate was The Beverly Hillbillies, about a bunch of country folk who strike it rich after Jed Clampett finds oil on his property. Then his kinfolk told him that California was the place they ought to be. Henning was born and grew up on a farm in Independence, Missouri, then became a big time Hollywood producer, so it isn’t hard to see something a bit autobiographical in this show.
Petticoat Junction was also somewhat autobiographical, but this time from Paul’s wife, Ruth. The hotel was based on her grandmother’s and her recollections growing up in a hotel next to a derelict train track. The show is about a tiny hotel located between Pixley and Hooterville connected by a train line with an obsolete engine. When the show starts, this train has been forgotten by the railroad company that owns it. Petticoat Junction gets its name from the water tower located near the hotel, where the three daughters of the hotel’s owner go bathing at the title sequence of every show.
The third show was its most surreal. Green Acres was a reverse Beverly Hillbillies. This show was created by Jay Sommers, hailing from… NEW YORK?!?!? It was based on a radio play he’d written in 1950, but got folded into the Hennimg-verse. This time two city folks say goodbye to city life and trade it in for farm livin’ in ol’ Hooterville. Oliver Douglas has an unrealistic expectations on the idyllic nature of country life but soon runs into the reality that work is harder than he thought it was. Plus, all of his countryfied neighbors are bizarre weirdos. Well, except Arnold. Arnold is swell. And a pig. Eva Gabor plays Oliver’s wife, who as mentioned in the title song pines for her life in NYC but somehow fits in better with the Hooterville locals than her husband.
Crossovers between these three shows were fairly common. Characters like Sam Drucker ended up being regulars on multiple shows, making it impossible to say if they belonged to one show or another. Of the three, The Beverly Hillbillies was more self contained, since in-story they were pretty much on the other side of the country. Hooterville was a central locale for both Petticoat Junction and Green Acres, though.
And just where is Hooterville? Like Springfield from The Simpsons, the snow deliberately obscures its true location. It may be based on nostalgia for Missouri, but hints across the three shows could put it in North Carolina, Kentucky, Pennsyvania, or anywhere in the South or Midwest.
The shows were pretty much ratings hits in the 60’s, but were all eventually cancelled in 1971 when CBS decided to cancel all of their countrified shows as part of an attempt to get the younger, urban demographic. Gone was the Paul Henning Trilogy, Mayberry RFD, The Jim Nabors Hour, and others. Or as Pat Buttram (who played Mr. Haney) said, “CBS cancelled everything with a tree in it — including Lassie.”