I'm right in the middle of assisting in preparing business continuity plans for my company . . . we're taking a look at what is available from the American Red Cross. I'd suggest everyone do the same:
American Red Cross Disaster Services . . .
I generally don't keep food in the trailer because this time of year it's a freezable. In the summer, I worry about the heat causing spoilage.
I spent years volunteering as a red cross DAT (Disaster Action Team) member, so I've my share of disasters. Here are some thoughts . . .
First, the Red Cross has a lot of useful information on family disaster planning. I'd take a look at it.
Second, disasters that wipe out neighborhoods and community services are important to plan for, but don't forget to plan for small disasters, too. Most (but not all) of the disasters I've been called out for came in the form of a simple house or apartment fire.
Make copies of your important documents (travel documents, birth certificates, legal papers, your will if you have one, financial account information along with instructions on how to access your various accounts, your wedding/children's photos, etc.) and store them in a fire-proof lockbox. In this digital age it's not a bad idea to also make digital copies of all those documents & pictures and put them on a pair of USB "thumb" drives, one which gets stored in your lockbox and the other kept somewhere away from home, like with another family member or at the back of your desk drawer at work. (Not in your car, which might be destroyed in a house fire or broken into and allow a thief access to all that important information.)
And there's something else you should put on those USB drives: pictures of your everything and everyone in your home. Pictures of people so you have them to help you locate and identify missing family members, pictures of your house and everything in it for insurance and legal purposes. (This is a good idea, even if you don't have insurance, because if a neighbor's kid starts a fire or a fire starts due to someone's negligence or the water tower or a drunk turns your house into a drive-through their insurance will only pay for the damages and losses you can prove. It's also a great way to provide the police with documentation that might help you recover stolen belongings if your house gets broken into.) Taking pictures of each room from each and every corner, plus pictures of every closet and contents of each drawer and shelf and anything of particular value is an easy way to maintain basic documentation of your belongings.
As I said, keep two copies of your "security" thumb drive, one in your house and another somewhere else that's safe, but also remember to update the thumb drives once a year or so by picking a time, like when you file your taxes (so you have your end-of-year tax bank statements and other information), a birthday, anniversary that acts as a reminder.
One thing you should keep on-hand in your car or other convenient place is a list of your prescriptions, prescription numbers, the pharmacy where you get them, your doctor's names and an old pair of everyone's glasses. When the Red Cross rolls up after a house fire we'll do our best to get you replacement medications, but you have to be able to tell us what they are. Sure, your car might be in the garage if you have a fire, but it's good to have these things readily available and most home fires don't destroy the entire house so there's a good chance that either the bathroom where your medications are located or a car in the garage will survive.
On that same note, everyone knows it's important to make regular backups of your computer files, and there are lots of different tools that will help you do that. The problem is that most people keep their backups in a drawer next to their computer, so if a fire destroys their computer, it generally gets their backups as well. Since house fires don't usually destroy the entire structure, keeping your backups in another part of the house or in an out-building makes it much more likely that either your backups or your computer will survive.
One last note on large-scale disaster planning and emergency food. While it's nice to have a variety of food available when we're out camping, there are few things that can beat dry spaghetti noodles and cans of spaghetti sauce as emergency food. Assuming you have basic cooking gear, a stove burner, and a supply of water (everyone should have several gallons of water per person stashed away in case of emergency), spaghetti supplies are compact, store almost indefinitely, is an easy meal to make, provides good, balanced nutrition, and serving quantities can be readily adapted to large or small groups. For bonus points you can even adapt spaghetti to work for meat and non-meat diets by buying spaghetti sauce cans with and without meat in them and keeping cans of three-bean salad (which also store almost indefinitely) as a source of vegetarian protien. Since the same qualities that make spaghetti easy to store also make them great candidates for your kitchen pantry or for a food drive it's easy to keep your emergency food supplies "current" by buying a fresh lot each Christmas season and either rotating your emergency supplies into your household stock or donating them to a food drive. While you're swapping your food supplies around you can empty out those five-gallon water bottles you keep on-hand for emergencies and refill them with fresh water, too.