We've just spent a great week in Cavtat. We were treated as guests rather than customers - our hosts couldn't have been more welcoming or helpful. From being collected from the airport, to the advice on where to eat and what to see, everything was catered for.
The accommodation was simple, but clean and comfortable and the view from the apartment, balcony, hot tub and pool is spectacular.
The walk from town is quite steep and takes about 15 minutes, but worth it for the view and our hosts were insistent that they would take and collect us at any time, so shouldn't cause any problems.
Cavtat itself is quite small and quiet, but the restaurants and cafes are plentiful and good value. Dubrovnik is about an hour by boat or less than half an hour by regular and inexpensive bus.
Thoroughly recommended.