I just returned from a week in Aruba. Last Friday, I rented a Yamaha TW200 for a day to tour the island. My wife got herself an ATV, which are street legal there.
No problemo, just showed them my GM licence (and credit card!) and the guy gave me a map of the island, the key to the bikes, a quick lesson for my wife, and they sent us on our way.
We had an awsome day! And what a challenge riding through the 100 degree heat in the sand dunes in the desert, and then into the typical Latin American craziness in all the local neighbouhoods and the traffic-jammed centre of town. Lots of dented cars. They don't care!
My wife was the only ATV in the city. We pulled up to the high-end stores in the shopping district, she parallel parked the ATV and went in for a look while I sat and kept an eye on the machines!