My advise would be to check out the personality of any cruise line or ship. Some of them have a large percentage of young singles working on their mating skills. You don't want to send your parents on a cruise with a bunch of college kids or 20 somethings upchucking in the pool or fighting on the dance floor. It's been known to happen. Try to find a cruise that will appeal to their tastes and that is appropriate for their age range.