Hi Shawn:
I see that I misinterpreted your drawing, and the maximum width of the layout area is only 20’ and not 24’ as I assumed in my original plan.
I think you can work around this reduced width using several methods. The first and easiest one is to reduce the minimum curve radius to 4’, as indicated in figure 1. In that case, no major changes in the layout shape are required.

Figure 1 - Layout with 4’ minimum radius curves
Keeping minimum radius curves at 5’ is possible if the return loops are slightly nested into one another, as indicated in figure 2.

Figure 2 - Alternative with 5’ minimum radius
In both cases a 6’’ minimum distance is kept between the track centerline and the layout border, and 7’’ are kept between adjacent parallel tracks.
Have fun building your layout.
José Morais
Headmaster of the Lapa Furada RR