I spent a week in skiathos last year for a quick break. We stayed in La Luna Apartments with the best hotel manager on the planet Dimitri.
The island is as close to paradise as you can possibly get. The beaches were never crowded. The water was clear and the locals were very friendly. Together with this island not being very touristy and the food being absolutely amazing it was almost perfect.
It's another place, like the UAE where there is hardly any crime and therefore you feel safe wandering around the island late at night.
The Island has one proper road which runs the whole length of one side of the island, and a very regular bus service runs until late at night, although if you are nearer the town the buses get very crowded, in fact i have no idea how they managed to get that many people on there.