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 was the first of three consecutive movie adaptations of Jay Cronley novels in three consecutive years, produced by Hollywood. The subsequent adaptions were "Let It Ride (1989)" and "Quick Change (1990)."
The New York City building from which Andy and Elizabeth move out 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.
Director George Roy Hill had originally wanted Robin Williams whom he previously directed in The World According to Garp (1982) to play Andy Farmer. However when Williams received the script he felt the character of Andy Farmer was too low key for his comedy style. Williams was very close friends with Chevy Chase and suggested Hill offer him the role instead. Hill enjoyed Chase's work in Fletch (1985) and agreed to cast him.