If you are considering a Viking River Cruise - just do it! My Mom and I had so much fun and I think to narrow it down it was "the experience" overall. Feel free to reach out with specific questions but here's a quick overview.
1. The boat is quaint and beautiful. I loved knowing or recognizing most of the passengers. The rooms are small but comfortable. I would recommend spending the extra money for a balcony or french balcony because opening your door when you want is worth the money; especially in those cool locks!
2. The food was really good. Eating w/people you recognize and spend time with was great. The caliber of people on our ship was amazing. Just nice people all around. Beer, wine and drinks are "included" during meals so you never have to worry about a bill sneaking up on you.
We loved it. Very tight and cozy but comfortable. There is a refrigerator and heated bathroom floors. The amenities are awesome.
Amazing city. Go the day before to have more time. Recommend a more "private" intimate tour as the city is beautiful.