She was cast on "The Lone Ranger" in 1953, and then again on that popular series in 1955. Coates was cast in 1955 as Madge in the CBS sitcom "Professional Father". In 1955, she portrayed Medora De More in the two-part episode "King of the Dakotas" of the NBC western anthology series "Frontier." In 1956, she was cast in the episode "God in the Street" of another anthology series, "Crossroads", based on the lives of American clergymen. That same year, she appeared in a second religious drama, "This Is the Life", as Betty in the episode "I Killed Lieutenant Hartwell." She was also cast in 1956 as Marge in the episode "Web Feet" of the military drama "Navy Log". She guest-starred in David Janssen's crime drama "Richard Diamond, Private Detective".