The Westin does have car rentral, most are jeeps which is a must in my opinion. The rental place opens at 8:00am and the rates were $65 last week when we were there. The taxis were $5 each person each way, not sure about the cost of kids since we didn't have any. The cost quickly adds up so I suggest planning your days and rent when possible, the only issue was parking in Cruz Bay which we parked in the shopping area and walked vereywhere downtown.