Construction started with the acquisition of plywood, ceiling tiles (box; for roadbed), and Masonite hardboard (for backdrops; not implemented, ultimately).
Once a module was built, I covered it with a sheet of 3/4" plywood for the land and water surfaces, and then glued 1/2" ceiling tiles to the land area, to act as a roadbed for the track.
These are the cabinets upon which this layout, too, will rest. The modules are 4 feet deep (left to right in the photo), and all three combined will cover 8 feet (front to back in the photo). The two remaining cabinets in the back will act as workbench space.
Once all three modules were built in the garage, I moved them into the room where the layout is to reside. This is on top of the same cabinets that I used on the previous layout. The modules are bolted together with two 1/4" bolts on each side, for a total of 8 bolts in the set-up you see here. I subsequently cut and installed the backdrop panels, but found them too unwieldy to actually have up, so they were removed and never used again.