Once you and your luggage have arrived at your hotel via taxi from the airport, you shouldn't need a car for the duration of your trip.  The city is small, and with many hotels, shops and restaurants located within very close proximity, exploring by foot is a great option.  A walking tour is a great way to take in the sunny weather. 

Many locals and tourists prefer to go by bicycle or scooter.  Scooters and bikes are available for rent at numerous shops around town.

Taking a tour with Old Town Trolley Tours is a good way to get an overview of the city, and they allow passengers to board and get off at their own pace, to independently explore areas of interest.  A map of the route is available online.