According to ExpertFlyer, the Cape Air flight arrives within 15 minutes of schedule 78% of the time. When the flight is delayed, the average delay is 54 minutes. (The morning can be foggy up there on that hillside where they stuck the airport.)

There's no way I'd risk taking that flight. It's an easy enough drive down to Boston the day before, and then you can get up at a much more reasonable hour, as well.