I don't think that this episode was unnecessary filler at all. It has a few problems, such as the dialogue not being very sharp, but I don't think that's what this episode was about. It was for the laughs. I can't express into words how funny this episode is in particular. Not only that, but it also has its fair share of drama. And I love the ending so much. Don't skip Camp Castaways.
See also
Awards | FAQ | User Ratings | External Reviews | Metacritic Reviews