We chose a river cruise for the convenience, low stress, and all inclusiveness, as well as the locations visited in eastern europe. We are married in our early 30's without kids and were definitely not the normal river cruise couple. The average age of the cruise is about 60-65 years of age, with a few in their 40's, 50's, and 80's- at least they looked that age. Don't let the age deter you if you are young as most of the people were very nice and we made friends w/ multiple couples. There were a few groups of single friends, mom and son, etc., but predominantly married couples.
Our room was the lowest class and was very small, but adequate, and certainly no smaller than an inside stateroom on a larger cruise line. Our beds were separate, but you can squeeze into a single together if you wish. You will need an adapter for hair appliances, chargers, etc, but my wife was incorrect in thinking we needed a converter, as we didn't. There was a hair drier in the room and an iron could be obtained from the front desk. Movies are shown on one channel in your room on a daily basis- the same movie all day long as far as I could tell. If you read the information booklet in your room, which we didn't until the last day, you will find the list of movies for the week. Only one other channel is in english- CNN World, which I now prefer to normal CNN. The shower was good quality and never short of hot water. We had a window that ran just above water level and had a fair view, but certainly nothing picturesque- and it didn't open as the information book states. We peeked into a larger room, one level up from ours- D level I think- and it was MUCH nicer. However it was $500 more pp and I don't think it is worth the additional cost even now w/ all taken into consideration.
Budapest- if you have the chance definitely extend your stay here. It was one of our favorite locations and we wished we had more time. Cafe Girbaud was recommended to us and would recommend it to others. Wished we had visited a bath house and had more time for museums.