[1] In the mid-1970s, Friedenberg directed The Adventures of Frontier Fremont and The Life and Times of Grizzly Adams for the Utah-based production company Schick Sunn Classic Pictures, famed for four-walling their films instead of distributing them conventionally.
Notably, it was the screen debut of 20-year-old Madeleine Stowe, who later played the female lead in a more respectable Cooper adaptation, Michael Mann's The Last of the Mohicans.
Still working for Schick Sunn, Friedenberg directed the kitschy cult classic "documentary" The Bermuda Triangle, based on Charles Berlitz's 1974 book.
In 1986, two years before the release of the strikingly similar Rain Man, Friedenberg wrote the Hallmark Hall of Fame entry Promise, in which a carefree salesman takes charge of his epileptic, schizophrenic brother in the wake of a parent's death.
In his preface to the published screenplay, Friedenberg details his research into the facts of Maclean's life and that of his brother Paul (played in the movie by Brad Pitt).