I would recommend Naxos over Mykonos and with 12 days you could easily add Paros too. With Santorini, Paros, and Naxos you’ll get a good mix of different delights and some ferry island hopping too which is fun in itself. 1.5 days in Athens is perfect for most – 1 day for the Plaka, Parthenon, Acropolis Museum area; and a half-day to visit the Archaeological Museum which is a short drive or walk from the Plaka but hard to fit in one day along with the other sights.
Ferries between Naxos and Milos don’t start until June 7th (one each way, every day after that). Ferries between Santorini and Milos start April 28th and there is one every day in each direction. And there are always ferries between Naxos and Santorini. So if the dates work I would fly to Santorini (the longest leg) then ferry to Milos then Naxos and back to Athens. But if you need to travel between Naxos and Milos before the 7th then ferry Athens to Milos to Santorini to Naxos and back to Athens.
Kefallonia was severely shaken by an earthquake in 1953 and thereafter lost its quaint gloss. The picturesque northern port of Fiskardo however, escaped much of the destruction and remains to this day one of the main focal points for visitors to the island, so is a good spot for a stay of 2-3 days. Pretty, waterfront cafés and restaurants and a cosy, folksy feel predominate. Asos, between Fiskardo and Argostoli is a west coast ‘resort’ village that pulls in its fair share of visitors and the view down to Asos from the main island road is one of the most photographed spots on Kefallonia.
The first French airline was Société des lignes Latécoère, later known as Aéropostale, which started its first service in late 1918 to Spain. The Société Générale des Transports Aériens was created in late 1919, by the Farman brothers and the Farman F.60 Goliath plane flew scheduled services from Toussus-le-Noble to Kenley, near Croydon, England. Another early French airline was the Compagnie des Messageries Aériennes, established in 1919 by Louis-Charles Breguet, offering a mail and freight service between Le Bourget Airport, Paris and Lesquin Airport, Lille.
Where to stay in Crete: A 300-year-old hamlet surrounded by olive groves, Kapsaliana Village Hotel exudes peaceful authenticity. On a sandy bay just beyond Chania, Ammos Hotel smartly combines Scandi chic with a child-friendly vibe. Blue Palace Resort & Spa beats the (stiff) competition in Elounda with its spiral stone Isola Beach Club, thalassotherapy spa, and boat trips to Spinalonga island, a national monument just across Mirabello Bay.