I am planning to visit Spain in December. 2 weeks before Christmas. I will be in Madrid for 2 days, than Seville for 2, Grenada for 2, and lastly another 2 days in Barcelona. I can't seem to find a way to book a train from Granada to Barcelona. There is a night train that runs from Granada to Barcelona but I'm not sure where to book it. Should I purchase the Eurorail Pass?