The last stage of the Camino del Salvador is a long one with over 31 kilometers to walk. You have to arrive at the Cathedral in Oviedo from where you can take the Camino Primitivo onwards or alternatively you can finish your journey here.
Physically it will be quite a challenging day but you will cross through many villages and towns so you do not need to stock up on essentials.
If you are not in a hurry and love walking through Asturias you can finish your day in Mieres where there is an Albergue available for pilgrims.