Here's two Gameplay Videos, one leads you to Halloween Town, as the other leads to Atlanitca, you can easily tell which is which, the gummi ship music is always different. The Gummi Ship to Halloween Town music is unique though, as it goes through electric guitar tabs as well, this is clearly showing that Yoko had a bit of help from the Black Mages, as the style of the guitar sounds like something they would do.
http://www.youtube.com/?v=wgboaQDsrkU
^ Atlantica Gummi Ship
http://www.youtube.com/?v=FIFdoi75UBU
^ Halloween Town Gummi Ship
http://www.youtube.com/?v=wgboaQDsrkU
^ Atlantica Gummi Ship
http://www.youtube.com/?v=FIFdoi75UBU
^ Halloween Town Gummi Ship