I believe that for the days on board the Isabella II and on the Galapagos Islands not much, or any, money will be needed. We will arrive at Guayaquil early on the day prior to disembarking for the Isabella II and then there will be the final day back at Guayaquil. Any recommendations for what amount of cash it makes sense to bring, or if credit cards work as well as in the U.S. without extra fees, etc.? Thank you for the benefit of hearing your experience.