We visited Schwerin castle and everything went really well thanks to this very helpfulinformation from curmedgeon98. It is a beautiful castle and we had a lovely day exploring it and the amazing gardens and enjoying the cafe.
There was difficulty getting a taxi from Schwerin back to the train station, and it was too far for my elderly mother to walk. We had easily taken one to the castle from the train station, but then couldn't find one or summon one with an app. Neither Uber nor Bolt worked. My daughter walked all the way back, got a taxi to go pick up her grandparents, and then returned to the trainstation with them.