There should be plenty of "mature" (50+) travelers on Holland America Line. A couple of months ago I sailed with HAL for the first time - 7 night cruise on the Westerdam. Most of the passengers seemed to be 50-70+. I did not really care for HAL, a bit to sedate for my taste. However, I did meet some very nice people. One nice thing they did offer was a singles/solo traveler luncheon. I'm sure I was the youngest person attending the luncheon, and I am 56. Celebrity also seems to have plenty of mature travelers and a more "refined" entertainment. I have also been on a couple of 7-night Carnival cruises that had a high percentage of "mature folks." Although I did not care that much for HAL, I recently found myself booking another cruise with them because of the very interesting itinerary (17 nights, Lisbon to Rio).