The Panorama hotel is about 2 – 3 Km from Gerakas on the Porto Roma Road, about half way down the hill on the left. We stayed there in 2003 and the hotel goes back to the 1990s when it was built. Back when we stayed there it was a family hotel run by a local family. On Google Earth or Google Maps you can see its location by pasting these co-ordinates - 37° 42.958'N 20° 59.141'E.
As Sonic said, the naturist tend to go to the far end of the beach near the mud cliffs.