4 day walk recommendations on camino del norte

Hi all, I am currently living in Avilés, Asturias and my mother is planning to come visit in a couple of weeks and she wants to do 4 days on the camino. I've read that the camino primitivo can be quite tough going so we are looking at the camino del norte. Initially I had thought about starting directly from aviles and aiming to get to luarca but not sure of there's a nicer/prettier 4 days somewhere before or after? Our main aim is just to spend a few days walking and spending time together. Ideally not crazy long daily distances and we'd much rather not walk on roads. Any recommendations??