We are a family of 5 planning to spend 15 days in Spain over Christmas and the New Year. We hope to visit Barcelona, Madrid, Seville, Cordoba and Granada, travelling by train and car. Between Barcelona & Madrid, we will be staying 8 nights. How should we spend the other 6 nights - 2 each in Seville, Cordoba & Granada? We've heard confliciting opinions about Seville and are not sure if we should spend more than 2 nights there. Appreciate any advice.