Here are a couple more photos I found of the Bimini Baths and Rainbow Gardens/Palomar Ballroom.
Below: The entrance to the Bimini Baths.
usc digital archive
Below: The Rainbow Gardens would eventually become the Palomar Ballroom.
usc archive
Below: Palomar Ballroom.
Obviously the same place.
I'm guessing it was originally the Rainbow Gardens by the early make of automobiles
and the rainbow shape on the sign that carries over to the Palomar days. Does anyone know for sure?
postscript:
I did find some answers at this web site.
www.iajrc.org/archive/palomar.htm
The article is written by Floyd Levin.
He was actually at the Palomar Ballroom on the night of the fire Oct. 2, 1939.