I'm planning a 2 week trip next year during may in northern spain and want to come up with a good itinerary. I plan to arrive in Barcelona and then go west through basque country, cantabria, asutrias, until hitting galicia. Is there any major cities absolutely worth seeing in any of the provinces. I know bilbao and san sebastian are particularly popular cities with alot to offer. I'm interested in the night life mainly but its not super important.