@Carey TeaRose - WOW 12 cu ft of plaster ! What a mountain, looks great by the way. One thing I noticed in your post of what you called the SG Upstairs layout, just across the tracks from Charlton Heston's Jeep is a small brick lithographed building. I believe I have the same building and its a "Parkville" Station by Chien. I have always dated it to the 1930's but honestly don't know. Perhaps you have some additional information on it. Also I will post below, Chien made another version of the same building but with much more elaborate lithography.
Here is the little station that I think I saw on your layout.
Here are views of the front, rear, and side of the more elaborate lithographed version of the same building also by Chien. Note that this station says "Toytown" vice "Parkville" and it does not have the windows in the rear punched out in order to provide more area for lithographing. I have little to no information on these items and if you have more information that you are willing to share I would most certainly appreciate it.
Well Carey, its rare that I think there is anything I have that could add to your fabulous layouts but maybe this little building is something you might seek out. Nevertheless, your layouts are wonderful and thank you for posting.
Best Wishes
Don