Lisa Douglas begins calling Hooterville "Hootersville." As mentioned in trivia for the whole series, the character's eccentricity didn't come out right away in the first season because CBS producers were already concerned Eva Gabor's Hungarian accent wouldn't be understood by viewers.
The closing credits list the following humorous line... "Tractor supplied by Hoyt-Clagwell."
A billboard at the Hooterville train station says "Vote For Coolidge"; Calvin Coolidge was president from 1923-1929.
Oliver's antique tractor is a Hoyt-Clagwell. The company went out of business 40 years earlier because Mrs. Hoyt and Mrs. Clagwell didn't get along. Mr. Hoyt then went into the waxed fruit business.