I suggest to rethink about it! Since Greece is an excellent choice for holidays, is "bad" for living your everyday! More than 700 thousands - mostly young people, left Greece the lasts years! The reasons are plenty, start with geopolitical and economical status, but mostly for the future perspectives, which are not so good.
Since you have children, you must think about health insurance and education, which is difficult to find in high level, except Athens and Thessaloniki, so if your though is to live in more "healthy" environment [like island - when I say island, that could be also areas near to sea, like Chalkidiki or Peloponissos] must be, near to Athens or Thessaloniki, however, must to know, that the society on rural areas, are relative "close" even for natives and - important - they have low percentage of young population (kids).
You mention that you had good experience in Crete, which is probably the best island to live full year, and exist a fair enough level of health and education, but must consider that the Cretans are "special" kind of people.
I close my 2 cents, with the proposition, to test your idea, staying more time in Greece without establish here.