Several posters have asked in the comments section about how to prepare for a real nuclear war instead of the fake one we were told about fifty years ago.
Here are a few basic assertions:
1. Cobalt-60 and other dirty bomb salts will definitely be used in the coming war.
2. Salted nuclear weapons are worse than you have been told and not as bad as you might imagine.
3. Three feet of overhead cover, in particular crushed rock, will protect you from intercontinental fallout for extended lengths of time in 75% of the locations you might shelter on the planet. This is a real Vault situation. You can't take shelter from the cobalt death shroud by piling up some suitcases around you in an inner room.
4. You will require some air filtration in order to avoid breathing in fallout. It doesn't have to be war grade filtration but it wouldn't hurt. It is not getting a couple bad whiffs in a single day that will hurt you - it is breathing in cumulative minute doses of radioactive salts over the course of months that is the problem.
5. In reality, cobalt-60 won't make the surface of the earth uninhabitable for five years. It will make the surface unpleasant for a minimum of three months. You might be able to journey out during this time for emergency errands but you'd be a lot better off staying buttoned up for at least three months underground. Proper blocking of entryways into the shelter will be essential during this time. Correct monitoring of individual dosimeters will track radiation exposure and tell when somebody has acquired too high a dose and needs to rest for a while to recover. Sometimes people who sleep near entrances or are in parts of the shelter too close to the surface can silently get radiation poisoning unless each individual is monitored. It is impossible to know what kind of radiation levels to expect, save to say that places in the wrong wind patterns could see brief cycles of 100,000 rads or more aboveground. Some areas might see little or no fallout at all, no matter how dangerous the salts used in the warheads are.
6. The natural forces of weathering, water and wind will begin to decontaminate the planet immediately, mostly by washing off and concentrating radioactive particles in sumps, lakes and runoff areas. These areas will be deadly for any length of time if you encounter them for at least ten years after the death shroud. Most places with some drainage will see a gradual reduction over ten years that will result in livable areas and soils that can be cultivated again.
7. The biggest problems in surviving the cobalt death shroud after shelter will be access to clean drinking water and food. I would recommend you expect to store one year's worth of water at subsistence levels before turning to filtration of rain as a source. It is hard to beat water distillation for cleaning out radioactive contaminants.
8. Protective gear is advised aboveground for several years following the war, at least until you can secure a plot of land that radiation survey shows is clean and safe without wearing protective measures.