Hi, Rural1,
(and I think you mean — arrive Oviedo Wednesday, and not “arrive Santander Wednesday” or else you are going to be doing some super speed walking. )
Welcome to the forum. I think most of us have anxiety and nerves before starting on a camino, no matter how many we walk, but I hope you can calm your fears before you set out. The route is well marked, goes through some pretty little villages, has some glorious mountain stretches (along with some inevitable asphalt slogs around Mieres and into Oviedo), and some really pretty scenery through valleys. And if you enjoy ancient architecture, do not miss the short ascent up to the pre-romanesque, 9th century Santa Cristina de Lena, a few kms after Campomanes. It is just gorgeous.
August is a popular month for Spaniards on the Primitivo, at least it used to be before covid, so I don’t know what the numbers will be like for you. Do you have any reservations? There has been trouble in the early stages with workers filling up some pensiones, but since you are starting on a Friday you will probably miss that. Sandra’s albergue in Bendueños is very special, but many find that its location is a bit awkward for staging, but if you are going to take 5 or 6 days on the Salvador, it may suit you quite well!).
Enjoy, the Primitivo/Salvador is a great combination! Buen camino, Laurie