This episode takes place in October 1965.
The book Don reads in the hotel is "The Spy Who Came in From the Cold" by John le Carré.
The title is a reference to Don taking his children to Disneyland - Tomorrowland is one of the areas in the park. It also refers to Don putting his past behind him (moving on from Anna, Betty and Faye) and starting a new life with Megan.
A young model is named Carolyn Jones, "like Morticia" which refers to Carolyn Jones from The Addams Family (1964).