Today I visited an open house exhibition from my country's government fund for maintaining historical important builings.
They showed how to burn lime, make houses with clay elements, traditional roofing and other stuff like pigments and clay.

The people there were mostly small businesses that are very specialised or conservators.
I must admit, to buy these services, you need a lot of money. But to have a look what "was" once possible and maybe find a craft that one like it can really give you a good impression what can be done without industrial production, all on a small scale.
If you can become a regional specialized person for a cerrtain skill, your future will be bright.

So I really recommend going to some scientifical based exhibits for traditional crafts to have an idea what might be useful in the future...