12 Monkeys,
Ok, here is a concept, not complete. If you like it we can refine it. It still needs 2 sets of crossover switches, some track fitment work and switches for the Inglenooks.
Here is double main that will be a nice runner - mostly O84 and O72 with some O96 for the inside curves. I always liked "balloons" versus loops when the space is available.
Yards usually bore me if you are not modeling something from a railroad. This is a big difference between O and smaller gauges. A 4' x 15' area is usually needed for a yard. I have been trying to incorporate Inglenooks for yards. These can be used anyway way that you like and also provide operational/play value as a shunting game. FasTtrack switches also limit yards not having any numbered switches for tight track centers.
There is space in the bend for some single service spurs if you desire those.
There is still space for scenic items, buildings and such.
Not sure if elevations can be incorporated.
I tried to setup the walls, which I assumed were the blue lines for baseboard and then make a baseboard for the tracks.
The aisles are tight in a couple of areas, but there is some space to be gained with table shaping.
Here is a view from the door, a track plan overview and the SCARM file.
