In January my wife and I are going cruising in the Caribbean for 2 weeks. We will be visiting various islands, many of which have their own currency. I have a very good credit card that doesn't charge me for exchanging transactions in local currencies to sterling and I have an SPG Amex for purchasing on the ship. Is there a currency that is accepted on most island's without having to keep exchanging money before going ashore. Both Linda and I are avid explorers, so the usual excursions sold on the ship appeal to us less than getting off and going to explore places ourselves.
Any suggestions for places where it would be good to do this? Also any suggestions as to where this would be inadvisable or dangerous to do so?