Y'know:
The more I think about it, the more I kinda like the idea that all the episodes so far have taken place during a single year.
It makes me wonder if they could actually be arranged that way. I mean, forget the broadcast order and just go with internal evidence: for instance, is there any reason why "Apple Family Reunion" couldn't happen before "Applebuck Season"? After all, reunions are a summertime thing, and apple harvests tend to come in early and mid-fall...