Are you cruising to Alaska? Cruise line excursions can be very expensive mostly because they have a back to ship guarantee. I have a list of excursions with Viator and they to have a back to ship guarantee and often much less. These are a must see!
https://www.viator.com/widget/email/U00695220/W-bb022090-72ee-41c7-8ada-2b2dacb30a7b?width=600