I'd keep them in the plastic cans. Keeps dust and moisture out for the most part. When you get done shooting, just pop them back in. They aren't that much larger than the roll of film.
If you want to keep some kind of structure to your load of film, you could tape a bunch of plastic cans together in a block. I'd put them all in a big ziploc freezer bag or some other kind of waterproof container.