I have never done a cruise before, ocean or otherwise, but my friend and I who are both in our 50s decided to do the Passau-Budapest Danube Waltz. The advertisements were compelling, but they don't do justice to the stunning sights. Our flight to Munich was great; a Viking agent picked us up immediately and put us on a cushy bus to Passau....absolutely no problems. The boat, the Magni, is clean, new, tasteful, and we were greeted with a champagne cocktail. Our room was ready when we arrived, even though we were there before check-in time. It had ample room for our luggage and ourselves and was chic and well-designed--down comforter and smart finishes. No wasted space. A huge flat screen TV that offered CNN, BBC, and a few other channels, (that seemed to show American crime dramas only), as well as the weather, movies, and travel videos. The floor in the bathroom is heated!. We had the French Balcony room and could open our door and look out whenever we wanted. I was surprised at how quiet it was. And smooth too--I couldn't tell when we were moving or docked.
The food was delicious--mind you I am not a connoisseur---and certainly not adventurous with food---so I was pleased to see food I recognized. American cuisine along with local/European dishes. They have GREAT coffee machines--espresso, cappuccino, coffee, tea, hot chocolate---anytime of day or night.
Everyday there are activities planned--mostly bus or walking tours of various places--but you are free to go off and do what you want. I am not much of a group-tourist--I prefer to go on my own, but I did find that the 45 minute bus and/or walking tours did give me lots of information and afterwards we would go exploring on our own. Don't underestimate the places on the tour. Our first site in Passau was a cathedral. I yawned at the thought, but the place just floored us! Baroque style (get used to it--it's everywhere in Europe) and we even got an organ concert! There are other excursions you can do. We did Schonbrunn Palace but I wouldn't do it again. It was crowded, vast, and held so much ornateness and over-the-topness that I became overwhelmed after the first few rooms.