Daily News: It’s difficult to overstate the impact Walter Elias Disney had on America. He created indelible characters like Mickey Mouse and adapted others including Snow White. He mass-marketed the concept of vacation destinations like Disneyland. “A lot of people have one good idea,” says Sarah Colt, who directed and produced “Walt Disney,” a four-hour “American Masters” airing Monday and Tuesday nights on PBS. “Walt Disney kept having more.”