Ok making progress on the transfer and car rental front.
Carm is setting me up with airport to ferry (plus bottle water for the family and a dos x for me), ferry tickets, pick up from ferry and transport to American car rental at the airport. There is a shuttle from the car rental to take us back to the airport.
I booked the car online, I booked the full size with a manual. To my surprise they didn't take a credit card for the reservation. If I pay in advance through the site, am I going to get beaten up with the exchange rate?
Speaking of, I recall reading in this thread about not using your cc to pay for stuff on the island. I hate carrying cash. That really my only option? Also not thrilled with the idea of having to stop at a grocery store or bank to pull out a bunch of cash once we land. I don't mind a lazy tax of a few bucks if I can exchange at a bank before I leave, but a couple hundred bucks lazy tax is a bridge too far. What is my best bet?