Best way to install extra propane

I saw a 2017 Northern Lite with a big L P bottle somehow attached to the rear bumper.

Mounting a propane tank holder on those large back steps wouldn't be that hard..I am thinking of upgrading to a TC that has those large rear bumper/steps..Mount a single propane holder and hardware to strap it down,and use it on the spot with an extended hose from the TC propane box when parked..

With one propane line running the inside of the TC and the other with an extended hose just for an AC or heater,separate from the TC frig and stove bottle..

If those bumpers are sturdy enough,one could go with a 7 or 10 gallon tank for longer run times for a heater or AC..

Not sure what there rated for though..