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 a station wagon to 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.