At last, here's the track plan. The area is approximately 8' x 12'. Minimum radius is 36". As you can see, this is purely a switching layout, representing a coastal Texas town at the end of a branch line. Railroad operations in the town are handled by the Gulf Harbor Terminal Railway. The "mainline" road has yet to be named...probably something like Texas Coast Railroad, etc.
The benchwork is already partially done. It will be "modular" with sections ranging from 3' to 4' in length. The sections are being built in our garage and will be bolted together in the "train room." The layout will be 45" high. The backdrop will be 1/4" hardboard, painted to represent sky but with no other detail. In practice, the only section that must be removable is the one at the far left, about 3' long, because it will be in front of a window, which must be accessible in the event it needs replacement or repair.
All of the track laid on my previous layout will be used, to be cut out of the original baseboard by a handheld jigsaw. As in many if not most layouts...and certainly all I've built...there will no doubt be some modifications to the original plan as construction progresses.
All track is within a 24" reach. A stepstool will be needed for completion of the scenery at the very back (a 36" maximum reach) but, once in place, access to that will seldom be needed.
Prior to assembling the sections in the train room, additional lighting will be installed, using plug-in flexible wall lamps.