I'd prefer just to have a RMA page with a form that would be useable for the customer to put in the return box so I know A) who they are and B) what to do with the products in the box. When submitted or generated online, the form could also add to the Private Order Status a snippet about the return as well.
I use shipstation but don't take enough returns to justify sending a return label in every box.
The following link takes you to the page I created.
I usually have it setup so that it can't be used if you have not logged in. That reduces the use by people that are not customers. I have removed that function for now so you can see it. Hope this sample helps.
Stephen Lowers All-TerrainCarbonless.com, BlankBondForms.com, CollatedPaper.com, HandNumberingMachines.com