Summary
'Girl Next Door' is the theme of Noelle, and as such appears in songs relating to her.
It's split into two distinct parts:
('Girl Next Door' A and B, as heard in Ferris Wheel)
The melody also has an 'outro' of sorts, used to end segments of the motif:
('Girl Next Door (Extra)', as heard in Ferris Wheel)
This motif bears a striking similarity to 'Hometown (Extra 2)', as discussed on the 'Hometown (Extra)' Vs. 'Girl Next Door (Extra)' page.
Aside from this similarity, the 'Girl Next Door (Extra)' motif is heard in a couple of surprising places, namely in The Dark Truth.