Likely she will sleep most of the time so I wouldn't worry too much . Just remember not to leave her in the car and offer water at every stop. Don't freak out if she doesn't use the bathroom much or eat and drink a lot. Gator slept the whole way on our trip to FL which was an 18 hour drive that I did strait through. He also did not go to the bathroom even once the entire time!
Good luck and have a safe trip!