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 Owners suites were furnished shabby chic, at best, but it was fabulous having semi-private balconies on both sides of the boat. One side was enclosed by a railing and contained a table and chairs. The other side had rocking chairs facing out, and could be enclosed by a rope, although we did not request that when the captain made the offer. If it were too sunny, we could just switch sides. People did walk around on the top deck past our private areas, but that was fine. WiFi is supposed to be available only in public rooms, but we were able to get it in one of our cabins (401) because it was next to the captain's cabin.