Lierganes nr Santander has a station at the end of the branch line from Santander and it is worth leaving the van here and getting the train to visit Santander as we did. Most people will hurry through Santander on their way to or from other parts of Spain, but Santander is worth a look round, especially to get your first (or last) taste of the tapas served in the local bars.
This was a perfect first night stopover and I would recommend it as a first/last night stop if you are using the Santander Ferry. It is FREE to park here and there is a water tap but that is about it. If you are just off the ferry and need fresh produce there is a small supermarket in the village.