I think it's a matter of opinion, but be aware that you really need to consider behaviors as users jump back and forth between form pages. Browser behavior when clicking the back button is unpredictable.
I'd put everything on one page, for starters.
I LOVE temporary records!
I store temporary values such as those you describe in a table. When the perm record is saved, I delete the record.
I also store the ID of the record in a cookie.
Next time the user clicks into the site, I check to see if that cookie exists. If it does, it means user exited before doing a permanent save. SO, If it does, I delete the record.