The lesson here, is do not take the last Plane/Bus/Ferry/fill in the blank, to return home
Sure, if you were vacationing in Mexico and used the seasonal airlines called Sun Country, you might have been screwed when poor weather cancelled flights. I can relate from a layover in Philadelphia.
Yet, I also know to not use the last option if I can. Ferries between islands is one example. If you miss the last one, you might be spending the night. So why add stress and take a return trip earlier.
Be sure to fill up the gas in your car rental before returning the car to the boat dock at Sandy Point Landing North Caicos.