I wrap the planted potted so the medium does not shift around with packing tape. I put a layer of wax paper between the medium and the tape. Sometimes I add a layer of moist sphag between the medium and the wax paper. I wrap the plant in newspaper or magazine paper(not as messy). Then fill around the plant with packing peanuts or strips of paper. You want to make it as light as possible yet you want to keep the plant tight enough in the box to prevent any shifting without causing damage to the plant.
Definitely write - Perishable - Keep away from Heat and Cold - on the outside of the box.
For bare rooted, I wrap the roots in damp sphag, wrap some paper around the sphag and place them in a bag lightly tying it.
Bubble wrap is great to use instead of packing peanuts or newspaper
Unless the roots are cut, I wouldn't use the cinammon.
I send Priority mail so it arrives within 2-3 days of mailing or UPS Ground.