In May 1963, several months after this program aired, Natalie Trundy (Ellen Marshall) suffered a ruptured disc in a car accident, which required a year's recovery in a back brace. This event broke the momentum of Trundy's promising return to acting.
James Doohan (Mr. Johnson) is one of 4 regular Star Trek (1966) actors to have been in The Twilight Zone. William Shatner was in Nightmare at 20,000 Feet (1963) and Nick of Time (1960) . Leonard Nimoy was in A Quality of Mercy (1961), and George Takei in The Encounter (1964).
David Opatoshu (Mr. Dorn) also played the head of another place with strange secrets; in A Taste of Armageddon (1967) he was Anan 7, head of the council on planet Eminiar VII, in which the Enterprise landing party were also unable to leave, having been condemned to death by the computer-fought war.
The vehicle driven by the main character Philip Redfield is a 1959 Chevrolet Impala convertible.
Notable similarities to Star Trek: the Valley technology includes shields, transporters, and replicators, even if they don't use that name. James Doohan (Mr. Johnson) was a regular on the original series and David Opatoshu (Mr. Dorn) was a guest star in A Taste of Armageddon (1967). Dorn shares a name with Michael Dorn, who played Worf on Star Trek: The Next Generation (1987) and other Trek projects.