For a house of apartment........ three inches from the opening side drill a 1/2 inch hole on the floor and then place a 1/2 inch round piece of metal in the same.
This will allowed you to open the door those three inches in safefty in order to find out who is there.
The only way to force it open would be by forcing off the whole frame......better with a metal door.

"If you are ready you are not"... Ponce

Re: the portable toilet. Clay cat litter weighs a ton when it's wet. Use a paper-based cat litter or plain old sawdust.

Sue

Arizona Iced Tea comes in very sturdy gallon jugs. Also, stay away from the plastic storage bins that have the lid in 2 parts which hinge. These are very convenient to use until you put one where it is subject to water dripping. (rain, leaky pipe, etc.) Then they fill up with water. The ones that have a separate one -piece lid are better in that regard.

I think you could get by with just three 14 gal bins; One for clothes/ tools, one for food and one for water. Should keep you happy for a few days.