The Rhine River flows from Switzerland, through Germany, into the Netherlands, and ends at the North Sea. One of the most picturesque areas on the Rhine River is about 2 hours from us. It is between the villages named Sankt Goar and Rüdesheim. We have done 2 river cruises in this section so far and I could definitely do it again.
The cruises generally run from March to October and is approximately 2 hours in length (4 hours round trip). Along the route to and from Sankt Goar and Rüdesheim there are approximately 20 sites to see, most of them castles. The views are gorgeous all through the cruise season, but especially in autumn with all of the beautiful colors.
We have cruised with both Köln-Düsseldorfer and Bingen-Rüdesheim companies. The first cruise was with KD and we needed tickets ahead of time because the boat was completely full. It was very nice, had great food, and friendly waitstaff. This past October we took the Bingen-Rüdesheim company cruise and it was also fantastic. We did not book any tickets ahead of time and the boat was not completely full. I would judge this on the time of year you are in the area and how big of a group you have.
I would say the difference between the two companies is that KD is a bit more fancy, while still being casual. They had white table cloths, where Bingen-Rüdesheim just had normal tables. Both cruises have announcements in multiple languages about the castles and different sites you pass. Both boats also serve beer, wine, and desserts.
The villages of Sankt Goar and Rüdesheim are great places to spend a few hours before or after your cruise. They are a little bit touristy with multiple souvenir shops, but adorable all the same. Their biggest attractions are the large castle ruin in Sankt Goar and the sky bucket to a large monument in Rüdesheim. On the sky bucket you can even drink small bottles of wine.
Any of our friends and family who come to visit will be taken on one of these cruises. It is way too beautiful to pass up.