Following many requests for help with impossible or ill-thought out itineraries, several DEs for Greece have asked if we can put this information at the head of the forum as a "sticky".
A visitor from a large country such as Canada, the US or Australia could be forgiven for looking at a map of Greece and assuming that they can choose any 3 or 4 islands for a two week trip and that travelling between those islands will be easy, given that distances in Greece would seem small to what they are used to. Over the past couple of months there have been dozens of new posts on the Greek forums from visitors who want to see islands, "W", "X", "Y" and "Z" but appear to have little or no idea where these islands may be in relation to each other, and most importantly, how to get from one to the next, if indeed you can.
Travelling within island groups is usually not too difficult, as there are regular inter-island ferry routes and even some flights available. It's when you want to travel between different island groups that problems can arise due to distance, time of the year, ferries that only run on certain days, or lack of routes at all. That's when peoples' plans come to a grinding halt.
So, please, before you start a new thread on the forums to ask for assistance on what may be a totally impossible to achieve itinerary, spend a little time to familiarise yourself with a map of Greece. Take a look to see the various island groups, where they are located, and more importantly, where they sit in relation to the other groups. They might only be a hundred miles apart but in many incidences, the only way from A to B is via Athens, which means additional expense and valuable holiday/vacation time spent in transit.
Remember too please, that any domestic journey in Greece will use up the better part of a full day so please consider this aspect when contemplating an itinerary of Athens plus three or four islands in a 10-day visit, it's simply not a practical use of your valuable holiday time.