Is Caliborn's Masterpiece simply Homestuck itself? The kids being "stuck" in the juju can be a metaphor for their position in the enlarged timeline Caliborn creates when he partially commandeers the story from AH.

The symbolic themes of the Masterpiece certainly imply this, but there’s also the Literal aspect of the story, which could have deeper ramifications during the Epilogue. Still, that is a totally valid take on the Masterpiece.