The trick will be to thread the needle between "dumb luck" and "railroaded" for the differences.
The story about how Jack the Mechanic adapted his job easily for Steampunk Heaven, but lost his job and became a shiftless bum adventurer in Monster Land where machines don't work makes perfect sense but isn't that interesting.
The story about how his machine shop was crushed by a falling Sword of Destiny is just a generic fantasy story.
You'd have to get really deep into exactly how the same person, with the same goals, ends up choosing completely different paths based on the world.
To really drive it home, he'd need to have almost identical opportunities and deliberately chose different paths.