We are heading to a wedding in Northern Spain next month. Wondered if renting a car is the most reasonable way to get around between the cities of Bilbao , San Sebastian, and the Castillo where the wedding is? Or should we just take cabs around once we get there?
If you mean this Castillo, then I would rent a car for that portion of the trip. Between the two coastal cities, there are hourly slow trains (2.5 hours, www.euskotren.es) or faster, more frequent buses (1.5 hours). Within a city, you're usually better off with cabs and public transport, versus parking and navigating.