I've seen that one listed a lot, just not in a 5 day format.
I'll definitely check them out. I appreciate everyone directing me to specific cruise companies. It's a bit frustrating that my internet searches just keep bringing up Viking, Avalon, and Tauk over and over.
This is really good to know. Even 3 days isn't bad as we'll be checking out other places by train as part of a longer trip. I just wanted a taste of the river cruise experience (I've never been on one).