How to construct all scenarios based on user journey?

In one scenario I can write CasperJS to simulate the human interaction on the page and then BackstopJS can take the screenshot, but is it possible to construct all the scenarios according to a human user journey?

E.g.:

- User journey:
Land on page A, login and click a link -> go to page B, do something and click a link -> go to page C and submit a form.

- Scenarios I hope:
Scenario 1: land on page A, BackstopJS takes screenshot for page A,
Scenario 2: from page A, login and click a link and go to page B, BackstopJS takes screenshot for page B,
Scenario 3: from page B, do something and click link to page C, BackstopJS takes screenshot for page C.

Current questions:
Page B and C can't be directly accessed by visiting the URLs, I need login and some interaction in previous page, so to test scenario 3, is it a MUST to write all the previous steps (A->B->C) in its onReadyScript?

Not sure if i describe the question clearly.