Greece in May or September is as good as it gets. The summer crowds are gone, the tavernas are open, and the Aegean is warm enough for a swim. A solid two-week trip for two typically costs around $4,200 once you count flights, island ferries, and boutique stays.
You do not need to drop all that cash at once. Spreading the cost over a longer timeline lets you lock in lower shoulder-season prices now while keeping your monthly budget completely intact.
Remember that a 0% interest period is a strict deadline, not free money. If you still carry a balance after 18 months, the card's standard variable rate kicks in on whatever is left. Pay the $233.33 each month so your debt stays back in Greece.