It also looks like the paper bail and the right side of the platen could use a good steel wool polish.  You could even use the more recent square feet, such as the ones found on any Royal X, KHM, KMM, KMG, HH, and FP models.  They should interchange fairly well.  And as for the ribbon, keep looking into other Royal typewriters, and if you can buy a carcass cheap and it still has its spools--get it.  You'll also have spares for your typewriter.  Again, to a point, Royals have some interchangeable parts.