Eric wrote:Make sure you have enough water in your vehicles to hold you for at least a day in case something happens to the vehicle carrying the water. Just a suitcase (2.5 gallons) should hold you for 2 or 3 people for the first day, as long as you're not exerting yourselves.
Prepare for the case that you get separated from your truck and that you will have to spend the first night without them - we always keep sleeping bags, a basic set of clothes and some food and water in our car.
Gate has the ability to send you back should they get the impression that you are unprepared and likely to suffer. They will not be counting water gallons or cans of food (they're not your mama), but if it looks like you packed for disneyland and not a camping trip in the desert they might ask an extra question or two.
Simply seeing that you are asking this question tells me that you're prepared enough to not worry about gate.