Don't know when passenger service ended. Wiki says 1951. Nor do I know whether or not it was regarded as a section of the Golden State, or a connecting train or a connection to some other train. I suspect not since the one passenger train each way was essentially a local. The railroad was built as the San Diego and Arizona, later called the San Diego and Arizona Eastern, but was controlled by Southern Pacific. It looped through Mexico, the Mexican portion being the Tijuana and Tecate. This was 148.1 miles to El Centro CA with 44 miles being on the T&T. The rest of the way to Yuma AZ was on a Southern Pacific branch 9.1 miles to Calexico on the Mexican border, thence back into Mexico for 52 miles on the Inter California Railway, then 9 miles back in the US to Yuma. Total 218 miles San Diego to Yuma.
My mother-in-law talked once about riding on it during WW2. She was returning from San Diego to Pensacola after spending some time in San Diego while her husband's ship was in port. (I never met the man. He died before I met my wife to be.) She had three small kids, not including my wife who was born in 1947. They were in coach. She probably never even ever saw the inside of a Pullman car. Beyond their budget. She talked about the whole passenger clientele being somewhat creepy, particularly when she realized they were outside the US and in Mexico on two different sections of the route. The whole San Diego to Yuma time was on the order of 8 hours. I do not know what the entire trip time was, but their destination was Pensacola FL. Yes, during that time many people took multi day/night trips in coach.