John Peterson wrote the novel "The Secret Hide-Out" as well as this series of children's novels which were adapted into a TV series that aired from 1983-1985?
The Secret Hide-Out: The Secret Hide-Out is a children's novel written and illustrated by children's author John Peterson, who also created "The Littles". The Littles: The Littles is a series of children's novels by American author John Peterson, the first of which was published in 1967. The Littles:  Sixteen years later, Peterson's books were adapted into "The Littles", an animated series by DIC Entertainment. The Littles:  The television show ran on ABC Saturday mornings from September 10, 1983 to November 2, 1985 for three seasons and 29 episodes.
The Littles