Take a wonderful walk from the South to the North or reverse and discover the tracks of former settlement from the last two thousand years. You will also pass Saría's biggest cave where the cache ist located.
According to legend a local shepherd became a hero when he killed five pirates in this cave some hundreds of years ago. Pirates oftenly robbed the island. One day five pirates reached this cave. The shepherd pretended to offer them a small meal but instead he poured hot milk into their faces. He used the short confusion and shot the pirates with their own rifles.
One possibility to get to Saría is to ask one of the captains in Diafáni (Níkos Orfanós, Geórgios Protópapas or Vassílis Baláskas) to bring you to Jáplo Bay in the south of Saría. You may then walk for about 3 hours to Palátia where the boat will pick you up to bring you back to Diafáni.
The cache is inside the cave. The coordinates will lead you to the entrance of the cave. Refer to the hint if necessary. I have rated it T 5 because you need a boat to get to one of the trailheads.
Take care because it might be slippery either through rain and/or goat dung!
Good luck!