use a door as a workbench?

Yes, but they also make wardrobes from the same construction as fast- food boxes. Doesn't mean it's a good idea.

OTOH, Ikea's cheapest "hardboard" material, as used for the backing of wardrobes and such, is proof against industrial cutting lasers. No idea what's in it, probably asbestos and adamantine. Won't cut though.

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember DDS saying something like:

Following some advice on this very newsgroup some 13 years ago I set up a plain hardboard door on some fruit boxes and used it as a computer desk, purely as a temporary thing. Guess what? The temporary nature has proved to be fairly long-term and it's still supporting a PC, CRT monitor, printer, speakers and assorted junk.