Your idea about a journey from Origin to the Market and on to the End seems solid, but it strikes me as a bit too predictable. A way to change that and at the same time to factor in the Excuse is to include the notion that a path is hardly ever as it is planned from the beginning. Journeying the path might change your understanding of it. That is where the Excuse might come in. After having stocked up at the Market, you venture on toward the End, but instead, you hit the Excuse as the third of four fixed way points. It signifies a point where you suddenly discover that the original plan just doesn't fit you any more. There you might lose something important or even turn into a different person.
I think if you were to include something like this, it would favour the variant of laying out the timeline in segments.