If you want to “go outside”, I mean outside Crete, then visit Santorini. You can have a day trip or even longer, if you have time.
I used to thought, Santorini is the most beautiful Greek island. But I see how it’s getting more and more crowded, plus my Greek friend convinced me that other islands are more beautiful, so now I even think that Crete is much more interesting than Santorini. Well, we’re changing all the time. 😀
Crete is a very touristic island. Everyone can find something nice, including luxury, hiking, budget and even nice, calm areas. The island is big enough to provide enough space for everyone – at least that was my impression from 10 years ago.