We are going on a Caribbean cruise with a few other couples in a few months and I need some help. It's a week long cruise with 2 formal/semi-formal dinners. There will be 4 ports we will visit. Any suggestions that would fit into one carry-on bag? My biggest concern are sandals, as I love to bring about 4 (not including flip flops). Should I stick to a neutral metallic color or be bright and colorful? How do seasoned cruiser do it?

Forgot to mention, I prefer not to wear shorts and t-shirts every day.