Thailand in May or October means you beat the worst of the crowds and get better prices on resorts. You'll spend your days on quiet beaches and your evenings eating local food without the usual tourist rush.
If you want to handle the $3200 cost without paying interest, you can use the Discover it® Cash Back card. It offers a 0% intro APR for 15 months on purchases and balance transfers, which helps you break down the total cost into smaller chunks.
Remember that the 0% intro APR is a temporary window, not a gift. If you still have a balance on the card after the 15 months end, you will start paying interest on the remaining amount.