I rented a Jeep when I visited Kauai. I simply upgraded my rental car to a Jeep at the airport. However they had a strict policy against traveling off road. There may be companies that rent Jeeps for backroad excursions and things and that may be a better bet if that's what she plans on doing. Also Jeeps are everywhere there and scream tourist so I'd advise against leaving any valuables in it, especially if its a soft top. Last year I visited Maui and in every turnout/parking area along the Road to Hana you could see piles of broke glass from vehicle windows. Just some info hope it helps.