The Cyclades are a popular and worthwhile destination within Greece. My own itinerary included a mix of hotspots and hidden gems.
Of course, what's a trip to Greece without some time in Athens? Plan to spend time here either at the start or end of your trip. I ended my time in Greece with 4 days in Athens, although many people only spend 1-2 days here and that is enough
For reference, I went to Greece in October and it was HOT. Here's some general, warmer weather inspo for what to wear in Greece