The Daytrippers (1997)

Eliza D'Amico thinks her marriage to Louis is going great until she finds a mysterious love note to her husband. Concerned, she goes to her mother for advice. Eliza, her parents, her sister Jo, and Jo's boyfriend all pile into the station wagon and go to the city to confront Louis with the letter. On the way, the five explore their relations with each other and meet many interesting people.