Hi! I am planning to backpack the islands (Santorini,Folegrandos and Milos etc) and Athens but I'm uncertain whether to book hostels and ferries in advance because it's the start of the high season. I will be travelling to Greece around 10th-12th July up until the 31st July- 1st August, I really want the freedom to choose where I go and for how long. Unfortunately I can't go any later in the year. How much leeway does travelling in July give you? Any advice from experienced backpackers to give to a newbie?