Ken S,
I wouldn't be concerned about Atlas availability.
Generally, on the layout plan, I don't really see what the switching area at the bottom will do for operations. Is that the connector for expansion?
Spurs on railroads and railroads try to be as much straight track as they can. Our model railroads have to get more curves due to space restrictions. That doesn't mean that one should make spurs kinked. Backing cars in and uncoupling/coupling doesn't work well with the curve in the spur.
Search the internet for photos of industrial areas served by rail. Aerial photos help.
Make the area fun by having a manufacturer and a customer to permit picking up fulls, dropping off fulls, picking up empties and returning empties. When you expand, one can move further away.
I think that you will find the GG track and Ross switches or an all Ross layout, easy to work with and cut custom pieces. The Ross switches have a good selection of numbered switches. The #4 and Regular 11° are nice for yards and spurs. Good motors that work with any control method. The O42's seem a little wiggly.
