Hi TheHathaways, welcome to Cruise-Chat. Hope you will return from your cruise and be as addicted as the rest of us are
I haven't done that particular excursion, but it sounds like a great way to see the lay of the land. Normally, the excursions have a rating that will let you know how strenuous it is. Even on the ones that have been rated extreme physical activity, I haven't had too much trouble and I can guarantee you, I'm not that fit
Please let us know how you enjoyed your cruise when you return, I'm betting it will be a good review! Best wishes and once again, welcome aboard!