Hi dlepera,
When I hear happy music and accordion, first thing comes to mind is Yamaha's.... all-time favorite kind of styles: The Schlager styles.
If you are familiar with the Assembly function of the Style Creator you can replace a couple of parts of the preset style that are closer to the song with those from another style that fit.
Of course, you will have to play the intro and outro by your self.
(Sometimes I am using Main C or D for the intro before going to Main A for the first verse, in case I have to use a preset style as it is) .