I recently built a sky house in Terraria. After I did so, a bunch of NPCs appeared as expected. The Guide took up residence in a room in the house, as well as the demolitionist.
However, the Merchant and the Nurse are just wandering below the house, close to the rope. They have rooms allotted to them according to the housing panel, but they just don't seem to be going up.
I tried walking far away and waiting a bit, as well as saving/reopening. In both cases they still come out at the bottom.
How do I get them to get into the house?