What can I safely put in a tongue box?

I'm looking to put a few things on the tongue.
Hoping to put a battery, propane tank, and two 5 gallon gas cans. To my inexperienced self it sounds like an explosion waiting to happen.
My common sense says to keep them apart. Maybe tongue box in the middle, battery in a batt box on one side, then propane holder on the other side.
In some pics I see some of these items mixed in the tongue box, and also see propane stored inside the trailer--is that a no-no?
Love the forum!
Hoping to put a battery, propane tank, and two 5 gallon gas cans. To my inexperienced self it sounds like an explosion waiting to happen.
My common sense says to keep them apart. Maybe tongue box in the middle, battery in a batt box on one side, then propane holder on the other side.
In some pics I see some of these items mixed in the tongue box, and also see propane stored inside the trailer--is that a no-no?
Love the forum!