After James Dean died, Simmons went into real estate. He owned the Hollywood mansion Errol Flynn once inhabited and rented it to Andy Warhol when he and his crew came to town and shot several films including Imitation of Christ (1967).
Lived with James Dean during the making of Rebel Without a Cause (1955) and up until Dean's untimely death in 1955. They would often arrive and depart from the set together.