Has anyone done a river cruise in Europe? We are specifically looking at the Rhine River at the moment but open to more.

My brother and I are planning to take our parents on an anniversary trip (50th). My family, my brother and his girlfriend, and my healthy but will be 78 year old parents.

Right now, its between that or Costa Rica. My parents have never left North America together, and my mom has never been overseas at all. Our heritage is mostly German with a little French so I thought they might enjoy this.

Any experiences you can share?