I'm on the road so I don't have my brochures. We are looking at the 16 day sailing so that might explain it. When you look in the KD brochure, their 16 day sailings are on Viking Pride and Viking Neptune. I'm sort of surprised that Viking doesn't have all of the KD cruises in their own brochure. From what I've read, KD should be a great experience. One option we were looking at for a shorter cruise was Peter Deilmann. They have a one week Rhein and a one week Passau-Passau that goes to Budapest. We are going in October and Deilmann doesn't operate any of their longer cruises at that time. One reason we are looking at the long cruise is that we want to go through the Main-Danube canal.
good luck, marc