It's only a half hour or less drive to lots of hotels in Singapore. Then you'd be in shopping areas where you can get a taste of Singapore before leaving.

Name hotels in Singapore are expensive, but several hotel credit cards offer certificates for free nights for signing up and meeting spend requirements. And book hotels in Singapore early. I've found the least expensive rooms go and you might have to book a more expensive hotel.

Some cruise lines offer an air package that if your flight makes you miss the cruise, they will get you to the next stop.

I don't usually recommend travel insurance, but if this is a one-time, expensive trip you might want to consider that, too. But read the fine print so you know what is covered. And some travel insurance companies are very difficult to get reimbursement from.