Our hotel-sunny villas-was directly in front of Skaros rock and it was too tempting for a little hike! You have to have some decent shoes, the steps to even get to the 'base' of the rock are uneven and broken in places and once you are climbing up the path can get jagged and precarious.
We saw people up the very top of the rock but we got about 10/20 metres away from the very top. I think you need to literally climb the rocks to get higher and it's a bit daunting and we're pretty fit and young.
I would definitely not take children too far up as the drops are severe and there is little or no safety rails.
The views are really great, you can look back to Imerovigli and across to Oia on the right and the rest of the caldera on the left.
A real treat is getting round to the little church/monistry of Skaros rock. It was closed when we were there but there were candles lit inside so somebody has a pretty spectacular walk/hike to work and back!
In total we spent 1.5 hours there and back stopping for lots of photos. Remember to take water and perhaps go after breakfast before it gets too hot!