“Cusack has hustled to earn a living — she couldn’t afford to finish her degree at the University of North Texas — whether as a singing waitress near a Fort Worth freeway; on a cruise ship crooning Burt Bacharach songs; or as a jazz chanteuse in an underground wine bar for $40 a night. Sitting in her cramped dressing room at the Cort Theater the other day, Ms. Cusack didn’t seem bitter.”