I am planning a ten day trip to East Germany in April.(D and her fiance are professional musicians there) We usually travel to Europe every year to visit friends and have fun. But the last two years our busy schedules have prohibited this. So I understand your desire to pack a lot in to those days. We arrive and depart from Prague and will probably not travel any further west than Munich. Really, it’s only eight days if you consider the first and last days are travel days only.
A cruise is different experience since the mechanics of travel are taken care of for you. (wake up one days it’s Istanbul and wake up the next it’s Venice) But when you are responsible for all of those transfers, train trips, car rentals, hotel check ins, taxi rides bus trips et al------it can wreak havoc on the experience for the short time that you are there.