Hello all! I've been replaying Harvest Moon and that got me thinking about NPCs like Kai who would only visit during the summer, or Skye who only visits at night. Would this be possible to do in SDV? I'm not stranger to coding custom NPCs but I'm not sure if it's possible to have them warp "off map" when not in use. Is this a thing that could be done? Maybe by setting their default position somewhere like 1,1 on a rarely used/unused map and then their start position somewhere in town for, say, the summer schedule? But I don't know if that'd cause routing errors.
It's definitely possible with a SMAPI mod, since you can add/remove the NPC anytime. It might be possible with Content Patcher too by conditionally changing their home position to somewhere inaccessible in Data\NPCDispositions. (If you're interested in the content pack approach, you could ask in #modding on the Stardew Valley Discord since it has some content pack modders who could help more.)
Through SMAPI, definitely. Though Content Patcher will not change a spawning NPC's location. I have a custom NPC who is SUPPOSED to change starting locations after conditions were met, however she stays in the old area.