If you’re searching for a quiet place, go to Agios Nikolaos. There is no proper description for it. It’s not a village, it’s not a beach, it’s not a camping spot. It’s simply a place.
There is a small church on a low promontory, equipped with a bell. You could pull the string, if you dare. From there, you might like to stare at Sithonia and Athos. There is little else to do.
There is a fishing village nearby, but don’t go there, you’ll just scare the locals. You could also fish, the place is ideal for such an endeavour.
How to get there ? Easy. Go to Paliouri, and on the east side of the village you’ll find a road sign that says Gallini/Agios Nikolaos.
When the road ends, you will have reached Agios Nikolaos, Kassandra’s middle of nowhere.