I suggest using cereal boxes. That's what I use. Cereal boxes are thicker than the soda boxes.
My process (once I figured out the dimensions I needed) has been to cut out the pattern, fold and glue appropriately with the printed side out, spray paint the outside with a dark color (gray or drab green, even used tan on a couple), and finally print full-page labels that I wrap and glue to the entire outside. I spray a few coats of a flat clear-coat to finish things off and help seal against the elements.
The end result leaves a pretty clean look.
The little strips on the bottoms of the boxes are just to temporarily cover up my hometown that I used for a location as a little joke.