We live in Michigan and have been advised that our personal lines auto insurance does not cover us when out of the USA! If you have a MC/Visa Gold Card or better you have up to $25,000. in coverage for any loss. I once ripped out a oilpan of a van sightseeing and the repair was just over $300.00, my MC was used and did cover it but had to pay the bill and submit to MC when home which they promptly reimbursed to me as I had receipts and proof of paying the bill.
FYI, if you have a American Express credit card they have a extra called "Rental Car Premium Insurance" and if you rent a car pretty much any where in the world and use the Amex Card it automatically charges your card a one time fee of $20.00 for the rental period which is alot cheaper than the daily rate by the rental cars on the island!
Greg