PX, huh... While PX may or may not be an issue, the survival issues are still the same. So if we were to be hit by an asteroid is it PX? Maybe not but the same conditions could exist.

Survival is the same. Learning your surroundings is key to survival. Your environment will dictate the best course of action.

Water: essential in any case. Clean drinking water is easily produced by several methods. Distillation is easy to accomplish in most survival scenarios...

[link to www.thefarm.org]

Food: Katch, Kill, or Kultivate... Simple, huh??
Well, not meaning to make a pun but all are basically self explaining. Many things caught can be cultivated... rabbits for instance... Wild rabbit can be caught and bread in many bunkers. their dropings can be used for fertilizer for shrooms and worms, sunlight not an issue.

Shelter: Bunker, cellar, cave... Personally I would prefer not to live under ground for very long. However, we aren't making the rules. Extended stays under ground could be boring and possibly lead to mind issues. But, if you have to live underground for some time, the above list will help keep you busy and should help with the solitude and darkness.

Best case scenario: Water, Food, Shelter... Build a cellar or basement (BUNKER if you will) and supply it with enough food, and water to sustain the amount of people that will be there for a few months, a year would be better. Rotate the supply through your household on a monthly bases and keep the fresh stuff for the stock pile. Learn how to recycle "everything"... what you throw away may have value for the coming changes (an empty coke can, can become a reflective surface, a drinking cup, a water distiller, a cooking pot...) you get the idea...

My comments may seem trivial and common knowledge, but in the END you may not think so...

Good luck in the future and be prepared....