As someone who's only slightly geriatric (41), but who also has two jobs that mean being online and available all day every day, cruises are the best. You get to see new places, someone else takes you there while you sleep, and best of all, you're nigh unreachable. No phone service, and the ship internet costs like $20 an hour.
But don't necessarily believe people when they say "Oh, just get a crappy, cheap room. You'll never be in there." It depends on how you plan to spend your time. Are you planning to spend your sea-going days in the bar or casino all day? Or maybe spend all of your time fighting for a chair in the sun but somehow also out of the wind on the deck, even when the weather inevitably turns bad for a day? OK, then a cheap, crappy room is for you. But we go to chill and relax and generally "get away." So we get a nice room with a balcony where we can go out and sit if the weather's nice, and we can sit inside on our couch and look out our big window if it's not.
That said, I'm liking this oldsters RPG idea. In the Discworld books, there's a group of extremely old warriors who many people laugh at, until someone points out that there's only one way you get to be an OLD warrior. By being better at being a warrior than just about everyone else.