I'm not sure how best to handle NPCs that have no homes. In Ultima VII, every NPC had a home; of course, there really weren't that many NPCs. The entire world was much smaller than it at first appeared. But the devs clearly intended for this to be a real working feature, and only dropped it relatively recently. The decision not to have a home for every NPC had to have been made long before they dropped the schedules.
Perhaps they will eventually give us some insight.
