This is our second cruise. Our first was a 4-day Western Caribbean, and we stretched ourselves too thin on shore excursions. At the third port of call, we didn’t bother with any of our scheduled activities and just wandered around aimlessly. It worked out fine.
That said, I’m definitely scheduling any ukulele-related activities I can find. Everything else is flexible. (Well, maybe not my joints, on account of the arthritis. But that’s not important now.)