Be especially sure to store copies of your ID, social security card, and birth certificate. Loss of ID on the streets is frequent and without backup can be disastrous. Don't max out your checking account thinking that no one will take a check from a homeless person. Of course they will. Pay your storage fees promptly by mail, with checks or money orders.
Checks are cheaper.
There are places in this city where you can find lockers, even some free ones. Unfortunately, I am not allowed to tell you about them, because they aren't intended for you. This brings us to the debate over the relative merits of backpacks, bags, carts, etc. This is a matter of personal preference and physical ability. Carts and large backpacks mark you, but do what you want or must.