Miss Hathaway is a lesbian. This is helped along, obviously, by the Real Life lesbianism of both of her actresses — Nancy Kulp (in the TV series) and Lily Tomlin (in the film).
So that would make her crush on Jethro a front?
Lesbians do sometimes tend to hide their sexuality by pretending to be attracted to someone of the same state, yes.
Elly-May could potentially be an FTM trans man, as she seemed actually quite pleased when Ms. Hathaway confused her for a man, and her natural discomfort wearing feminine clothing.
Critical Dissonance: Upon its premiere, critics roundly panned the series as unfunny and hoped the series would flop. Viewers, however, adored the show to the point where it was the top-rated program in the country for the first two seasons, a remained in the top 30 until the ninth and final season.
Humorist Dave Barry: "If you surveyed a hundred typical middle-aged Americans, I bet you'd find that only two of them could tell you their blood types, but every last one of them would know the theme song from The Beverly Hillbillies."
Ensemble Dark Horse: Sonny only appeared in ten episodes, but his actor received lots of fan mail.
Vindicated by History: The show remains a staple of syndicated television to this day, and still brings in decent ratings, mostly on digital subchannels dedicated to reruns of this nature, so much so that it's hard to believe that critics absolutely hated it when it first aired.