I was looking at the photos of SP's rebuilt RDC at http://users.snowcrest.net/photobob/rdc.html and was wondering if the SP turned the car at the end of the line or used a locomotive on the blind end of the car.
Referring to the Willets to Eureka remnant operating on the NWP, I believe the car was likely wyed at each end.
However San Raphael, or someplace nearby would've had a turntable, though something tells me if that car was regularly on a turntable someone would've got a photo, not sure of date the car was single-ended as a wreck rebuild either as I believe the RDC replaced the conventional "Redwood" in 1959, while the service was cut back from San Raphael to Willits sometime in the sixties.