According to Wikipedia, "The film was mostly shot in Southeastern Vermont, including the towns of Windsor, Vermont and Townshend, Vermont using locals as extras. The Townshend Common today has an unusual souvenir from the production of Funny Farm: to make the trees on the Common look as if it was mid autumn, the film crew dyed the leaves, which killed all of the trees, except for one in the middle of the Common. Today, the ring of newly-planted trees around the edge of the Common are significantly shorter than the much larger one that survived the filming of Funny Farm (1988)".
This 1988 movie was the first of three consecutive filmed adaptations of Jay Cronley novels in three consecutive years produced by Hollywood. The subsequent adaptions were 1989's Let It Ride (1989) and 1990's Quick Change (1990).
The NYC building that Andy and Elizabeth move out from in the beginning of the film is The Apthorp Building. Residents have included Nora Ephron, Al Pacino, Conan O'Brien, Cyndi Lauper, and Rosie O'Donnell. The average apartment price is $6.5 million.
One of two 1988 feature films starring Chevy Chase. The other was Caddyshack II (1988). Funny Farm was a minor hit while Caddyshack II was a box office bomb. Chase also cameoed in 1988 in The Couch Trip (1988).
The name of the country town in Vermont, USA was Redbud. This main setting in the film is a fictional place though the picture was actually shot in the American state of Vermont. However, there is a real life city in the USA called "Red Bud", it is situated in Randolph County, Illinois.
When explaining to the potential home buyers why they are moving, Elizabeth Farmer states "We're being transfered. He works for the goverment, high level, top secret." An obvious reference to Spies Like Us also staring Chase.
The film was released about only five years after the movie's title had been used for a 1982 Canadian production first released in 1983 which had the similar and almost same title of The Funny Farm (1983).
The teams playing in the first baseball match were the "Redbud Raiders" and the "Bartsonville Bombers". The team seasons tickets that Andy Farmer (Chevy Chase) left one of his fellow sports-writers at the start of the film were for "The Giants". The sports team names that featured on Andy's cap and t-shirt in the movie were for the "New York Mets" (baseball) and "Los Angeles Rams" (football) respectively.
The name of the country newspaper that Andy Farmer (Chevy Chase) wrote as a sports-writer for was "The Redbud Gazette". The name of the Manhattan paper Andy wrote as a sports-writer for at the start of the picture is never mentioned.
The trivia items below may give away important plot points.
The eating of an apple, by Eve, was supposed to have gotten Adam and Eve cast out from the Garden of Eden (according to the bible) thus it is a sign of betrayal. Elizabeth betrays Chevy's character on the first night in their new country home (paradise) by eating an apple after claiming there was no food left. Both main characters have the same initials as Adam and Eve, Andy and Elizabeth.
The title of the novel about four poker buddies who knock over a casino that Andy Farmer (Chevy Chase) wrote was "The Big Heist" whilst the title of the children's book that Elizabeth Farmer (Madolyn Smith Osborne) wrote was the "Adventures of Andy the Squirrel".
The film, starring comedian Chevy Chase, with the title "Funny Farm", and set in the countryside, implies that the movie is a farm comedy, but actually, as outlined by Rating the Movies, the picture actually "has nothing to do with farming". Moreover, given the slang medical meaning of the film's title as well, the film neither has anything to do with mental asylums / psychiatric institutions either.