This was one of three John Candy films released during the "Summer" of 1985. The others were Volunteers (1985), where Candy re-teamed with Splash (1984) co-star Tom Hanks, and Brewster's Millions (1985), which starred Richard Pryor.
Karen Austin (Sandy Chester) was only 28 when the movie was filmed, and is less than 12 years older than Kerri Green, who played her daughter.
Summer Rental was filmed in St Pete Beach, FL.
According to Tracey J. Morgan's book "Searching for Candy," John Larroquette had more screen time in a major subplot as a romantic rival, trying to steal away Sandy. This was eliminated when it didn't fare well with test audiences.
The movie in the USA was originally classified with a PG-13 rating but after cuts done during further editing were made the film was then re-classified with a PG rating.