Explain to me how if the federal government did not raise the debt ceiling that this would automatically equate to default? There's more than enough tax revenue to pay for the interest payments on the debt. The government would just have to decide what to pay for with the tax revenue coming in less the amount we borrow. I'm not saying there wouldn't obviously be an ecominc hit (as both sides of the coin rely on us constantly spending/borrowing)...but default is not the correct word.
But really...if you're seriously worried about an economic meltdown right around the corner then I think you should stop worrying about currency and start worrying that you don't have enough guns, ammo, food, means to travel/bug out, etc. The folks that would be least affected by collapse are the guys living almost entirely on the land in remote areas/up in the mountains.