You have several options when considering how to store your emergency kit. The size and age of the people in your family will determine what method you decide to use in storing your emergency kits. No matter what your choice, you will want to make sure that it is easily portable, and that you will have the ability to move it over long distances if necessary.
1) Backpacks are the most common place to store emergency kits. These are nice because they are easy to move and leave your hands free. If buy hiking backpacks your will be able to store a large amount in them. You will want to make sure that you get packs that fit you properly. You can attach sleeping bags and tents to the backpacks fairly easily. The only disadvantage to this is if you have several young children, it may be difficult to carry enough food for a family of five on the backs of two adults. This can also be difficult if you will have to carry your children as well.
2) You may also consider using plastic containers such as Rubbermaid. If you do this you may be able to fit the entire kit into one large container. You will want to make sure that it has wheels so that you can pull it behind you if necessary. This may free up one adult so that they can carry or tend the children when necessary. You will also want to make sure that you can easily fit it into your car.
3) Another suggestion which I have heard is to use a large garbage can (new of course). You will want a sturdy can with wheels. This would be easy to roll as well. The biggest disadvantage is that it may be difficult to fit the kit into your car.
You should make sure that your backpacks or containers would keep your supplies dry. You can divide the load with children to the extent that they are able to carry it. You do not want to overburden them or yourself, so pack as lightly as possible.