Think “Margin Call” on a massive scale.
Interest rates will eventually go up to reflect the risk of holding US dollars; other countries will eventually stop loaning us money.
It's possible that the US Government could sell off some of the Land/Resources that they claim in various states to help settle the debt.
A well - balanced portfolio should contain about 10% precious metals, and real estate under normal circumstances. Any necessity that you can get at today's prices rather than tomorrow’s inflated values makes sense no matter what happens.
I tend to think that people living in the bible belt outside the Metro Areas will be better off on their farms outside the many small towns.
There is no doubt that being debt free and living in a home with no mortgage gives one a better chance to survive. Just buy some hard assets such as gold or silver to allow yourself to pay your real estate taxes and some additional needs.
Unfortunately, many people can not get debt free in time to beat the collapse. So there is going to be a world of hurt, and life will have some big adjustments.
Will the cities burn worse than they did during the 60’s and 70’s. I don't know. Do everything you can to prepare for the worst and hope for the best. That's the way I have always lived, and it's no different now.