And do not leave it in the incubator at home it can only survive a day without water. I say you bring a heating lamp and a mister in your car and leave the egg in a cushioned container that you can leave on your lap.
It will probably survive I guess but it will make a mess. Anyway, I hope you figure it out. You did say you have a plug in the car so you can probably hook it up in the car and leave the incubator in your vacation place.
But she's leaving for vacation so it'll be left in the incubator to starve and die. I say your best bet is to bring the heating lamp with you and try to keep the eggs as warm it's supposed to be. Or you can try to bring the incubator with you with all the eggs. Don't forget the duck needs to eat.