Which TV series was originally pitched as "Wagon Train to the Stars"?

On March 11, 1964, Gene Roddenberry, a long-time fan of science fiction, drafted a short treatment for a science-fiction television series that he called Star Trek. This was to be set on board a large interstellar spaceship in the 23rd century, whose crew was dedicated to exploring a relatively small portion of our galaxy, the Milky Way. Roddenberry had extensive experience in writing for series about the Old West that had been popular television fare earlier in the 1960s and the 1950s. Armed with this background, the first draft deliberately characterizes the new show as "Wagon Train to the stars." Like the familiar Wagon Train, each episode was to be a self-contained adventure story, set within the overarching structure of a continuing journey, rather than being bound to the same location. With the notable exception of Star Trek: Deep Space Nine, all future television and movie realisations of the franchise would adhere to the "Wagon Train" paradigm of the continuing journey.