Don’t bet so much on a literal wheelbarrow full of money. The US has only two printing offices, and they work around the clock, mostly printing $1 bills, and can barely keep enough paper currency in circulation to support 5% of US daily retail.
To make matters worse, it prints proportionately less higher denomination bills, and most $100 bills go overseas. This means they are physically unable to print more money, or higher denomination money, for the simple reason that nobody can make change for it.
Critically, only paper money and coins are legal tender. This means that nobody has to accept any form of electronic currency or paper like checks. If there was a “paper run”, banks would be emptied of their paper within an hour, nationwide, and there is far too little in reserve to matter.
This could result in what could be called a “currency split”, in which paper money and coins are instantly deflated 95% (worth 20 times their face value), and virtual money hyperinflates. Just on this possibility, it would be a very good idea to have some mattress money in a safe place at home.
I don't like to keep much at home, what with living on the New Madrid fault line and tornado alley to go along with any other risks, but if shtf, it won't do any good in the bank or safety deposit box either, so it is a quandry what to do with the little we have.
Silver is good too, and if there is no crash, or great inflation, it is used in so many things, it is bound to get even better anyway somewhere along the line, course I haven't had much money to invest in things like silver.
When all is said and done, I think food, medical supplies, water, etc are all the things that need to get priority, as well as a plan to pay property taxes on one’s home.