I can remember seeing what is being called a roadshow throughout the 50s. My parents would take me into Center City Philadelphia to all the large extravagant theatres to see films like The Robe, The Ten Commandments, Around The World in Eighty Days, Pepe, Oklahoma!, South Pacific, Ben-Hur, Giant, for starters. They all came replete with overtures, intermissions, programs in the lobby and my favorite - bon bons! So I’m thinking roadshow wasn’t new to the 60s.
In fact, I recently got the roadshow edition of Since You Went Away! Wasn’t that the 40s?