I've got a copy of a Ronnie Rocket script that I believe is older than the one floating around the net. It has been through a number of rewrites over the years, and the one that I have is shorter, and there are things in it that have been altered , deleted or added to in many ways.

Ronnie Rocket , was intended to be a musical, the lyrics for Sycamore trees were not especially written for Twin Peaks, they were old ideas. I don't know about the tune though. Lynch wrote Ronny Rocket it just after Eraserhead I think.

Exerpt from Ronnie Rocket

Lound sounds come up and Terry goes running off crazily.
The Detective is frightened and now he's left the place
he was supposed to stay in, and he's lost. He's on a street
with large low class hotels. He stands in the shadows
in front of one of the hotels and overheards part of a
conversation between a hard low class girl and a smooth
greasy tattooed man.

       GIRL
I got idea, man...you take me for a
walk (she moves over to the guy)
under the Sycamore trees (closer)
the dark trees that blow, baby. In
the dark trees I'll see you and you'll
see me...I'll see you in the branches
that blow in the breeze....I'll see you
under the trees

       GUY
I'll twist your neck

       GIRL
NO, NO, NO, NO you won't...I'll
run away from you.

       GUY
I'll catch you ...I'll catch you
in the dark trees and kill you.

GIRL
NO, NO, NO.

complete script