Continuity mistake: The view out the back of the barn door when it's first revealed does not match the same view, just minutes later, in the final shot of the film. (01:55:43 - 01:59:12)
Continuity mistake: When Bing Crosby and Danny Kaye enter the club car on the train when heading to Vermont, Bing Crosby puts his suitcase on the floor next to the booth in which they are seating. In fact, Bing places his hat on the bag. The ladies enter the car, join them for a talk (and a song) but when the group gets up to leave the bag is missing.
Continuity mistake: During the Choreography number, Danny Kaye's hands/positions keeps changing during the beginning part.
Answer: The actors appear similar but they are different people. John Brascia danced with Vera Ellen in Vermont. George Chakiris danced with Rosemary Clooney in New York.