Late spring in Munich hits the sweet spot. The chestnut trees in the beer gardens are green, the weather is warm enough to sit outside with a pretzel, and the train ride south to Neuschwanstein isn't packed shoulder-to-shoulder yet. You get the classic Bavarian scenery right before peak summer airfare kicks in.
A solid week here covering flights, hotels, trains, and food runs around $3,100 from the US. If you do not want to drain that cash up front, spreading it across an interest-free window makes the trip much easier on your monthly budget.
Keep in mind that 0% interest is an 18-month deadline, not free money. If you still carry a balance on the Citi Simplicity card when that window closes, standard interest rates kick in on whatever is left, so set up autopay for that $172.22 each month.