Personally, I would like to display the title as:
if for example, I, from being the Champion, Job Change into being the Princess's Mooch -Story of a "Jobless" Champion and a Princess Who Together Find Their Happiness-
Because the first part just doesn't translate into that second part that the second part seems more of a follow up part to me.
PS. Anyone got a better translation for "Himo"? I just remember someone else use mooch but I don't really know what a mooch is.