Chuck, I imagine you are aware of the article on Hemet by John Signor in the 1st Quarter 2021 issue of the SFRHMS Warbonnet (maybe an inspiration for your project?). You might try contacting John Signor and/or the SFRHMS to see if they have more information on the structures. The article does have a map of the Hemet area that shows the location of railway structures and a number of industries, and the track plan. If you don't have a copy, back issues are probably available (I've always had good luck ordering).
The depot is apparently still there (I am in Michigan, so I can't go look...), and in use as a museum. http://atsf.railfan.net/depots/hemet.html They might be able to provide you with drawings or at least more information on dimensions and details.
Thomas thanks, Chad Baker who works for BNSF, he was in Hemet/San Jacinto and now San Diego just got me the plans, see my layout engineering report. I am aware of the book and the articles from John. Just rather go organic with what I can get for free by making friends with the layout construction.