I've been doing a spot of building work. The structures for the layout are all pretty straightforward, they are all in low-relief except the shed in the foreground, and that has been shortened to fit the board. There are no windows, only two sets of double doors. And all are built from concrete blocks!
They have been built from foam-core board (nominally 3mm, though about 4mm thick in reality) and like the baseboard, stuck together with hot glue. My early experiment with this method had butt-joins at the corners but the edge of the board with the soft foam showed through the printed paper as not being a flat surface, so this time I have interlaced the corner. Each side is cut to the full width, then the rear layer of card and the foam is cut away from one side of the join about 4mm deep, so that the other side can fit into it. This is actually pretty easy to do, and as seen below results in a firm flat surface right to the corner. It is probably stronger too!
The buildings are then covered in the Scalescenes block-work texture stuck on with Pritt-Stick. A little PVA strengthens any edges. I'm currently working my way through scribing each wall with a blunt instrument to give a little relief, as you can see it is surprisingly effective.
The remaining structures yet to be scribed. A new engine shed has been built, the one I built to try the method didn't have the right proportions.