Ok,
The only concern that I have is what happens when you stand in the aisle from the center to the windows? Does the slope of the ceiling force you to bend over?
I flipped your photo and used it as a background image in SCARM and tried to recreate the tables. The walls are the blue polygon outline.
Then, using circles and squares, (well, only circles), placed O31 circles to check for fitment.
You can put rectangle footprints in for accessories and buildings, then work the track around those.
The yard could be a little tricky on the triangle. I may try a wye on the center island and perhaps the yard in there.
Then, work the O27 line in.
SCARM now has 6"(imperial grid) option. If you have 5", it's an older beta version.