we did an 8 day Danube cruise on AMA waterways. this is a much better way to see those sights as one unpacks once. There is a castle/cathedral/something around every bend in the river, and if not, one can always nap. we had lots of free time, opportunities for guided tours and the dress code was casual. I took one blue blazer, khakis and dress shirts, and never had a worry about dinner dress. Meals were great, but most lunches were on our own in the towns. The boat pulls up to the shore, and we were literally in the heart of the old part of wherever we were. spent 2 days in Prague, bussed to Germany, then went on the boat to Budapest and flew home. We would really like to make the second half of that journey from BUD to the Black Sea.