We've got a slot for April delivery of a 2012 e91, and we're working out a tour route now. My S.O. says the sights need to include a castle. Do folks have suggestions for something that'll be open for visiting that early in the season, and open to our self-exploration? Guided tours mostly leave us feeling educated but not entertained. Our first time through the European Delivery experience; so far it's been easy as pie.