our rig is currently parked in our seasonal site in the dead of a chicago winter.
We had them bring out and hookup a 250# propane tank. The local gas company delivered the tank and it had a regulator attached to it.
The next day, the tech from the gas company came out, took thier regulator off, disconnected my regulator from my tank, and ran a hose straight off the big tank to the input side of the motorhome's regulator.
Works fine, and since the gas company did it i can only assume it is done the right way