re: Serious question about long term planning.

The kind of crash you are concerned about would almost certainly be accompanied with a major devaluation of the US dollar. If that is the case, you don't want cash you want assets (as in a big house is better than a small house). You will be able to trade assets back for a lot more of the devalued currency or the all together new currency.

People tend to want to prepare for mass pandemonium, but a situation more like Russia after the Soviet Union collapsed is far more likely. I am not saying it is likely, but total anarchy is way less likely. If the dollar collapses the value of assets relative to one another will be much more constant than there value relative to dollars. You will still use currency to trade from one asset to another, but you would not suffer the losses of those that were holding the currency.