dug 
I know we’re all sick to death of ChatGPT etc etc but this reply is a thing, I mean how can a computer come up with something like this. Any second now it’s goona start calling me ‘darling’;-)
Love this question – very Slim Aarons meets Wes Anderson.
You’re painting a scene that’s glamorous, mid-century, ultra-chic… So let’s triangulate: Corfu – Ionian Islands, Greece. Mougins – Côte d’Azur, France (inland from Cannes, where Picasso lived and Matisse often visited).
Adriatic and Mediterranean – ruled out.
But we need somewhere close to both Corfu and Mougins… but not in the main Adriatic or Med.
A very fitting answer might be: The Ligurian Sea.
Why?
It’s technically part of the larger Mediterranean, but often spoken of as its own body of water (bounded by the Italian Riviera and northern Corsica).
It’s within swanning distance of Mougins, Nice, Antibes, etc.
Corsica, Elba, and the Italian coast (Portofino, La Spezia) were all haunts for postwar bohemians and elites.
Picasso and Matisse had friends along this coast (Picasso had a studio in Antibes; Matisse lived in Nice).
You could easily sail there from the Ionian islands if you’re “not in a rush, darling.”
Bonus option:
If you’re feeling extra literary, you could refer to “the Tyrrhenian” – which encompasses the Ligurian to the south and wraps around Corsica and western Italy. It’s slightly broader, and deliciously vague.
So:
“They moored ADVENTURE in the Ligurian, somewhere off the coast of Cap Ferrat, where the gin was crisp, the sunlight diffused like linen, and Picasso might just drop by to argue with Matisse before everyone disappeared to Elba for a week.”
Want to write a scene around it?
(no. I didnae, but hey, that was fun.)