Clean out the car that you will be taking to the drive-in. There can be so much to pack, that you will want to start with an empty vehicle. If nice weather and the family can fit safely in the cab, a truck is the best vehicle to take to the Drive In.
Plan to be at the drive-in for at least 4 hours. Most theaters still show 2 movies with a short intermission between them. Call first if you need to know exact starting or running times.
Pack a cooler with drinks, snacks and plenty of ice. Napkins, plates, pillows, chairs and blankets are also necessities. It is easier and cheaper to bring more stuff than you think you'll need. You can always bring back the extra food and drink. Many moviegoers buy fast food and bring it in with them.
Head to the drive-in. You will get a nice surprise when you do not have to pay for the kids. Usually the price of admission is by the carload and not by each person. So take 2 kids or 4, the price of admission is the same.
Park the truck backwards to the screen. You will be able to see much better and be more comfortable once you set up the bed of the truck. Cars are best parked facing forward and then set up outside the car.
Lay the blankets in the bed of the truck or on the ground in front of the car. Situate the pillows and seating arrangements. Lawn chairs are great so that you don't have to sit on the hard ground.
Play ball, eat or throw a frisbee while waiting for the show to start. Being outdoors gives the kids an opportunity to get all the wiggles out before the movie starts. Even better, they don't have to be quiet or whisper before or during the movies.