Put yourself somewhere on the fringes of the worst destruction in Joplin, MO.
You house is damaged, parts of the roof are gone, most of the windows are out, your vehicle is greasy-side-up next to where the carport used to be, BUT YOU SURVIVED!
You've done the obvious: accounted for everyone present, shut off the electricity, water and natural gas/propane supplies, you've done a basic inventory of what you have on hand, you've even sent scouts out to your immediate neighbors to assess their situations. Fortunately, the scouts have all come back and reported damage, but no casualties.
What do you do next?
You pull your shelter-in-place plan off the shelf, and put it into effect. Now, busy members of your family are filling all the water jugs they can find, the bathtub, etc., to have a water source. You go to your gun safe and pull out the ready weapons you've ALREADY fitted to your family, and trained, then briefed the family members on. You do a Weapons Check. You establish Weapons Contingencies (when to wear them, when to carry them, when to leave them out of sight).
You make provisions to take care of your provisions. Your electricity is out, and you don't expect it back anytime soon, so all your perishable and frozen food will have to be make less perishable, by cooking, drying, etc. You assign that duty to someone (maybe yourself, since it's REAL important). You have a generator and 5 days worth of fuel for it. You have a council with your family to get their feelings on running that generator, knowing that if the area turns lawless, running a generator tells the lawless element "there are good things here, just follow the motor noise to get to them".
Several fruitful hours pass, and you decide that your next major move will be to try to get a tarp over the damaged roof. You have the tarps, but only one ladder, and you will need a skilled crew to do it. You're considering your options on getting that crew together, when you hear a bullhorn. You peek out of the house, and you see emergency vehicles down the street. A coordinated group of people is going door-to-door, examining structures.
The group eventually gets to your house. What are they going to do and what authority do they bring with them?
Start by reading this. It will tell you about the marking system they will use to identify their inspection, and what those markings say when they put them on your house. No, you MAY NOT refuse entry to this inspection crew. If you do, you WILL be forcibly removed.
Now, who can tell you to leave and who can't? Do you have any right of appeal? What if you get a yes from one agency and a no from another? What do you do? (This happened in 1996, right here in Stumptown, in the Great Flood. The Fire Chief ordered a residential Marina evacuated, and the Sheriff refused to back him up, said everyone could shelter in place. I got to enforce the Sheriff's good news and tell the smoke-eater brass to pound sand).
Generally, the Sheriff of a County has that authority, and he/she is the only one who does. Unless you know the Sheriff well enough, personally, to know that if you ask, he/she will make an exception for YOU, you need to be ready to Bug Out. A possible exception to the Sheriff's authority is if the Governor declares Martial law and sends in the National Guard (never active-duty military, he doesn't control them). So, if an ACTUAL Deputy Sheriff tells you to leave, and that Deputy says it's the Order of the Sheriff, you MAY NOT stay. You grab your bug-out gear and hit the road, however you can, in your case, on foot. If you don't have an undamaged place to go to, you will be directed to a Shelter. Generally, you will be allowed to bring ONE small bag of personal possessions into the Shelter. You will NOT be allowed to bring weapons, and you MIGHT be searched.
I've run shelters. I was trained to do that in the military. The military has rules giving Shelter Commanders huge authority, and that's for a reason. In a shelter, you have a LOT of agitated people crammed together in a small space. Shelter-ees cannot have it like Burger King, their way. That's just the breaks. Roll with those punches.
Let's say that you have a summer place out in the boondox, and you know it's safe and sound out there. How do you get yourself and your Bug Out gear out to that place?
Any way you can, hoser. This is where your negotiation skills will be put to the test. Essentially, you need a vehicle large enough to transport you and your family, and your essential gear. However, if all you can get is a mini-mobile, you will have to use that and make several trips, even if they are hours each way. The person you get the vehicle from needs to know that, and YOU need to have a way to get their vehicle back to them when you're done with it. Fuel, etc are also up to you, but don't put the cart before the horse.
If, for example, that Pacific Subduction Zone major earthquake (with Tsunami) has just hit the PacNorWest, I would NOT be bugging out to the Coast, even if I called one of my friends there and got the news that my place had survived. The problem is, lots of places WON'T have survived, and the entire coastal area will be a disaster zone. It would be REAL difficult to get by down there.
You have to Bug Out to where you can make do until you can rebuild your home and your life. You need to have made some of those plans before Armageddon, don't you?
Get busy, you have a lot of work to do.