The lead was originally to be played by Matthew Broderick. He dropped out and the whole part had to be re-written to fit Matt Dillon's acting style and personality difference. The Broderick character was very different.
The original name of the movie that was being considered during the filming was actually 'Sweet Ginger Brown' in reference to the Gin Rummy games featured in the movie. Obviously, this was changed prior to release. But a lot of the pre-production materials and local news reports of the filming of the movie at the time referenced this earlier title.
The Adventure's Inn featured in the Flamingo Kid was located in Flushing, New York just off of the Bronx-Whitestone Expressway at Linden Place. It was originally part of an Amusement Park that closed in the mid 70's. The restaurant and arcade remained open until the early 80's. A large multiplex movie theatre and a Toys 'R us now take it's place!!!!!!!!!