My family of six (88, 61, 59, 29, 25, & 18 years old) took the two Owner's cabins, which each can hold three people and are located on the top deck, next to the captain's cabin. The captain was always at the helm or corner pilots stations when we traversed locks or did anything tricky, and his mate was usually there, also. The captain was also very friendly, making a point to greet all the passengers and often welcoming us back to the ship.
I would guess that the average age of passengers was upper 70's. There was only one other person in the younger age group at 45 years old. The age of passengers only mattered because it limited the activities on excursions significantly. Most excursions only allowed an hour and a half to do anything. We took a 4 hour round trip to the Mount St. Helen's observatory (too cloudy to see), but only had a little over an hour there because that was the most any passengers would have liked except our group. We were the only ones who went walking on the trails. This made for pretty dull sight seeing. Even at a museum, everyone (except us) was pretty pooped after an hour and wanted to go before the allotted time was up. This should be taken into consideration when considering this cruise. If you aren't pretty sedentary, you'll probably find the trip more relaxing than you'd want.
The most enjoyable trips were Multnomah Falls and walking the trails at Mount St. Helens, although we had to walk quite fast since the visits were short. We also really enjoyed the Bonneville Dam visit. Going through the locks was quite memorable, and I think we traversed 8 of them.
The staff are young and personable. Actually, they're the friendliest hospitality employees I've ever encountered. However, they are not competent. The food service was incredibly slow. We took to bringing water into the dining room at lunch when we would otherwise have to wait for drinks service because we would get too thirsty. The waits were interminable. The same people who served meals also cleaned the cabins. They were very poor at this. I don't know if the staff weren't trained well or if there were too few of them, but I would have expected better.
The food itself was not good. It was generally bland. Fish like salmon and steelhead trout were overcooked, as was chicken. The only protein I had that was really well cooked was duck. We had lots of salads, and they had a couple of dressings that were very good. The worst dish was an entree they called deviled crab. It was a gratinee dish full of some creamy liquid and a few very tiny pieces of crab.
We didn't really take much advantage of the available entertainment as it wasn't to our taste. That doesn't mean it might not have been done very well.
I wouldn't take another American Cruise Lines trip.