Thanks for the feedback! The blacksmiths do behave more or less randomly. There's a state machine driving what they're working on: wandering, forging, smithing (hammer), or whacking (mallet). They will complete their task (taking any time to drink) and then pick a new task to work on.
I think the idea of putting it on rails and making various levels (where you know they'll get mad if you don't intervene) is a great idea for a different mode.