Marty Williams' Trailer is a location featured in Grand Theft Auto: Vice City Stories.
The Trailer is the home of Trailer Park Mafia leader, Marty Jay Williams, his wife, Louise Cassidy-Williams, and their baby daughter, Mary-Beth Williams. It's located in the Trailer Park surrounding the Sunshine Autos dealership in Little Havanna. The trailer is small and somewhat derelict but it is among the larger and less filthy trailers in the camp where it's located. Halfway through the game, the trailer is left abandoned after Louise moves out with her daughter and Marty is killed.
It is from this trailer that Marty gives his missions to protagonist Victor Vance. In 1986, during Grand Theft Auto: Vice City, the trailer and the entire trailer park have been cleared and replaced by an empty lot next to the new Sunshine Autos showroom.