Hi,
@alaskangirls, welcome to the forum. I have moved your post to the sub-forum on the Vadiniense and Lebañiego. The Lebañiego goes from San Vicente de la Barquera on the Norte to Potes and on to the monastery. The Vadiniense picks up from there and goes to Mansilla de las Mulas on the Francés.
Check out the posts you'll get to on this link. There is even a report from 2022!
I've walked both and would say that if you are interested in walking in the Picos, it's really only the part from Potes (near the end of the Lebañiego) to the pass at Pandetrave after Fuente Dé that has mountainous walking. The rest of the Vadiniense is pretty un-mountainous. Maybe a good idea would be to walk from San vicente to Fuente Dé and then spend a few days of day hiking in that area, because it is beautiful and there's a ton of hiking.