Be prepared for early morning excursions, not much free time when in a city.
If you've never been on a river cruise, be prepared for small cabins -- but with fairly efficient use of space.
Bring lots of vitamins and cold medicine to avoid getting sick on the winter trips.
They are very busy.......Be ready for a vacation when your cruise is over!
Not so much a tip for Rolf specifically but for cruise-takers in general: if you want a little more control over who you sit with for meals, wait until most people have gone in and begun sitting before you go into the dining area. Then you can choose who you sit with rather than them choosing you.
Make sure to mingle with the other guests, it's part of the experience.
Do take the Oxford, Highclere extension. It was well worth the extra money.
With the right attitude you will experience a wonderful adventure
We did not take Paris "extended" option because it was not cost effective at a glance but made other arrangements to stay with our group that took the "extension". The Viking rep at the hotel was so rude to all of us, limited help. Guests complained about bad accommodations, while ours was great!