Hi !
As a friend of mine told me, you only need one box.
As you may already take notes about exposition, N+ dev, film type, subjet and the like, you have ordered and numbered sheet of paper (or entries in a notebook) so the trick is to store exposed film in the exact same order than your notes.
Returning home, you unpack the film according to the porcessing notes et voila !
If you're a bit paranoïd, you can, as I do, double check using the film identification notches to ascertain nobody has messed up your ordered pile of film.