Like they said. If u go to the island...then u will want to rent a cart to see the island...but u don't have to....there is plenty to do without the carts
It's a small island and lots of people rent golf carts to tour it. I would bring the script bottles along just in case you are questioned about pills. Not sure about US but one of the questions of the customs form for Canadian citizens is whether you are bringing any vegetation into the country.
It is illegal in most places to have prescription meds outside of the original marked container from the pharmacy.