Huh! Well that is something, Jake. Wonder what those will cost, given their size? Precision Plastic sheets, which are 15 x 15 inches are about $10 a pop, as I recall. And if you make something really big, one sheet won’t do ya.
Not to belabor the point, but I’m not sure basswood would work for outdoor models. But what would work is Precision Board, which can be machined just like wood and, because it is a synthetic of some sort, will hold up to the elements. Not to sound like I’m trying to sell something (don’t want to tee of one of our posters), but the Pipers, down around San Diego, sell that material in plain sheets or machined to look like brick and stuff. Not cheap, but it will live in the nastiest climate. They have a website and run ads in Garden Railways, but if I told ya the name of their outfit, a certain poster would accuse me of trying to sell you their product.