It occurs to me that I could obtain a slightly better approximation of plot if I implement daemons that I will call plotpoints. These would be like seedstories, only they are triggered by predefined conditions rather than random factors. They could be used to advance the plot. One condition, of course, might be the ocurrence of a previous plot point. Other conditions would be actions taken by critical characters, things obtained or lost, and so forth. The big trick is to make the plotpoint check rare enough that it doesn't bog down the system.