After a period of research, studying Model Railroader back-numbers and some excellent small layout sites, I came across The Highland Terminal by Scot Osterweil in Model Railroad Planning 2005. You can see it described here.

The original plan is for a 6' x 1' layout that is sized for 40' cars. Since I had a little more space I resized it to 8' x 1.5' and to accommodate 50' cars. I felt that for the era I had in mind, 40' cars would be a little old fashioned.

I also flipped the plan so that the incoming track could be connected to an extension if I ever felt like building one. Without the flip the incoming track would go straight into a wall!