What is the ruling on fasting for expiation: must it be continuous and uninterrupted, or may it be spread out over 60 days?

You are obligated to make up only that day, and no expiation is required of you. This is because a traveler, even if he begins the day fasting, is permitted to break his fast, as the excuse of travel is still present. The Prophet, peace and blessings be upon him, did this. And expiation is not required of you, according to the more preponderant opinion.