When you make it to the wild west main street you must get a key from
the organ in order to unlock other places with other keys. To get the
code for the organ you must go from store to store and look for music
sheets. There will be 3 music sheets marked "1" "2" and "3". Each sheet
will have a set of notes on it remember the notes with the number and go
back to the saloon and input the notes as u saw them this will give you
the key to the vault.