So... I think I've found a program that does what I want. I may need to find a free alternative, though, in the next 30 days, so if anyone knows one, let me know.
Anyways, having mucked about with it I now have a flowchart showing how one makes a pick. Of course, I've not even though about steel or other alloys yet, or the more esoteric ways of getting charcoal, or correct usage of goblinite. And the manufacture of glass and ceramic pots are just stubs for now. And I've not even covered how to build the workshops. But I did laugh maniacally at one point, causing one of my housemates to judge me and my life choices.
So:
Anyways, with a bit of luck I think I can group stuff, such as fuel production, so that it can remain minimised for those of us who know very well how to get coal, thank you very much, or opened again for those same people when they're trapped underground by a siege and the caravans aren't coming, and
there's no coal left.
EDIT: Well, that didn't work. Does anyone know a program that produces a similar output, but where I can ideally click a little button on each box to tell the program to stop drawing all of the lines going into it, or similar?
2nd EDIT: Found a way to make the flowchart look less terrifying.