A Billion for Boris and Summer Switch are sequels to… the classic novel Freaky Friday, which has been made into movies on three different occasions (all three by Disney). Summer Switch is basically the same book, with the brother and Dad switching headspace instead of the girl and her mom. I don’t know if Rodgers got credit, but there have been a slew of father-son (or grandfather-grandson) mind transfer movies, including one with Kirk Cameron and Dudley Moore (can’t remember the name) and one with Corey Feldman and Jason Robards, and one with Fred Savage and Judge Reinhold, and one with George Burns, and… well, it was a genre unto itself.
But A Billion for Boris is the book that most delighted me as a child. It’s about a kid who gets a banged up TV that gets tomorrows TV shows. So he starts betting on sports. I believe it was made into a TV movie that nobody watched. The book is great.
I learned while researching this question that Mary Rodgers is the daughter of the legendary composer Richard Rodgers, he of “and Hart” and “and Hammerstein” fame. She herself wrote a few musicals, including the Princess and the Pea send-up, Once Upon a Mattress. Lots of talent in that family.