Great link to the route taken by your ship. Updated in almost real time - neat.
I see that the Icelandic road system goes all around the coastal parts of the country, plus selected valleys. Since you have your car with you, which roads do you intend to travel over and can an ordinary car navigate these roads at this time of the year (Autumn and I infer from your descriptions still warm enough to camp) or do you need a 4WD?
Safe journeys and TIA.