Rather than a loop to loop with a single main between , I prefer a dogbone on a deeper bench (30" deep) with the back main close to the wall with 2 or 3 train length sidings. They would be hidden behind a low backdrop, just high enough to hide a train on the back track. All the yards and industries are on the front side of the loop. The sidings on the back are staging. You can put a train on each track and then run them out as the schedule requires. This is a simple plan that will allow prototypical operation, just running in a circle operation, switching, virtually any combination to suit your fancy. Because in the visible area there is just one main/route through it, its easy to scenic well.
Just a thought.