It makes sense to Josy come alone. Not only would "balance" the Thanksgiving but also is Josy hometown too.
I mostly agree with
Better Cock Spock , at first my thought was that the cabin holiday would be later on, that MC would miss the DIK's Christmas (Mel's Preview) to be with Jill there. But now, thinking about the possibles branches Thanksgiving I'm leaning more towards that.
It would take massive work from DPC to have such different branches in two parts of the episode, it makes more sense to solve it all in Thanksgiving.