Cyclades

Naxos — Agios Georgios is a paddling pool of a beach, the old town does dinner with a playground beside it, and it's cheaper. Paros wins for nightlife you won't be having.

You answered it — Milos. Sarakiniko at 07:00, Kleftiko by boat, dinner in Pollonia. See Santorini once in shoulder season on someone else's honeymoon.

Deck class on a Blue Star is airline seating indoors if you want it — board early, claim a lounge table, luggage in the racks. It's the fast cats where deck means outside.