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.
Although this was the final film directed by George Roy Hill before his death in 2002 he did not in fact, actually retire after making this film. He stayed active as a drama teacher at Yale University until shortly before his death.