We're going on a river cruise

Lucky for us, the dress code is casual, but the service and food is first class.
https://www.americancruiselines.com/cruises/alaska-and-pacific-northwest/columbia-and-snake-rivers-cruise

Wow I never thought of taking one of those - it sounds unique. Question - how crowded are they? It gives the impression that there is not so many people on board, a little less amenities, but more space and perhaps more attentive service then.

I don't see these huge pools or casinos (which I am ok with) but what sort of amenities do they have? Do you spend more time onshore then visiting?

I went on a couple of those big cruises - in general I felt like cattle - everyone goes to dinner, then the show, then to breakfast, then to whatever it is--- I didn't like the crowding poolside - although it was nice to have a pool to dunk in.

They don't feel crowded at all! They are small river paddlewheel boats with the ambiance of the early 20th century. Here's a link on the boat we'll be on. It's my understanding that this boat carries 100 guests. The service and food are first rate even though the dress code is resort casual. All the patrons we came across were very friendly, and it has a good atmosphere. I didn't on our first cruise, but I'm thinking, I may bring my sports coat with me on this one.
https://www.americancruiselines.com/small-riverboat-cruise-ships/queen-of-the-west
If you have any further questions, feel free to ask. I'll try to answer them to the best of my ability.