Yes also did the Budapest to Amsterdam trip with Viking, highly recommend it. Small number of passangers (approx 100) and very enjoyable but still see a lot.
just this fall also did a bike and sail cruise in the islands off of Croatia for a week and was amazing. Boat was small (32 passengers ) and had a couple of guides that led the daily bike tours on each of the islands that we went to. Highly recommend if into biking. There are tons of these types all over if looking for something more active.