Tippi Hedren was unavailable to reprise her The Harrad Experiment (1973) role as Margaret Tenhausen.
In the welcome home scene, where "welcome" is purposely misspelled on the banner, the musician playing the Fender Rhodes is Doovid Barskin, at the time one of Capitol Records' A&R men. "We had to give him a part in the picture," producer Stevens quipped, "Otherwise he wouldn't release the soundtrack album.
Sheila's home was actually the Harold Lloyd Estate, in Beverly Hills.
Victoria Thompson, who plays Beth Hillyer, was blonde in the first movie (The Harrad Experiment). In this sequel she is a brunette (and the change is never mentioned).