I found the scan of the 1928 layout of the P&SR depot at 44 Fourth St in downtown Santa Rosa. The scan came from a Street Railway Journal, but I'm afraid I've lost the reference at this time.
And here for quick comparison is my plan to make it fit the space I had.
I tidied up the rough and ready 180 degree picture I presented before, adding the backdrop elements that were missing. Overall, not a bad interpretation, though the trackwork will require some home built crossings and several of the turnouts have to overlapped to fit into the prototype arrangement.
Unfortunately, like the real thing, this project has been abandoned into the mists of time.