In 1974, Keston travelled to Washington, D.C. with the Royal Shakespeare Company's touring production of "Sherlock Holmes", directed by Frank Dunlop, with artistic director Trevor Nunn. The company commenced its tour on 7 October at Kennedy Center's Eisenhower Theatre. A month later, the show began previews at Broadway's Broadhurst Theater, opened on 12 November, and ran 471 performances. It received four Tony nominations and two Tony awards. It gave Keston his sole Broadway credit for his performance as Sir Edward Leighton.