When shipping more than a couple of prints, we'll often wrap the prints around the core of an old box of paper, using tissue paper, then wrap this in bubble-wrap, then into the paper box. Hahnemuhle and Canson boxes are useful, as they open down the length, as opposed to Epson, Innova or Harman, which tend to open at he ends.
Depending on the size of the prints and the roll box, we may include the plastic ends which support the roll, or may exclude the actual tube core.
Prints always rolled face out, to match the original roll paper. For prints on HPR, we'll tend to not put more than 6 40x60" prints in one box. As a 44" paper box is over normal (UK) shipping sizes, we'd rather tape two boxes together, and take the small extra weight cost, than risk damaging the prints.