I am going to be going on an 8 day Duoro River cruise from Porto to Porto, and will be staying in Europe for 4 days post cruise. I am looking for suggestions as to where to travel to in that time frame. I have travelled through most of Spain and France and Italy but never south of Lisbon. Would 4 days in the Algarve be a good idea ? or Madeira ? or even Croatia ? where I have never been. We are 2 active, early 70 yrs.old seniors. We have been to many museums and cathedrals over many years of travel, but do enjoy being close to the ocean and visiting small towns and lovely country landscape. Flying home to Canada from Porto is not a necessity,as I can fly from wherever I end up. Thank you in advance.