what type of line to use to run propane

Hey all,
I am trying to get my propane side of the trailer figured out. I have my 2 tank regulator and now I need to know what you guys would plumb the propane line with. I do not have a long way to go inside. Maybe 4 feet from the tongue/tanks to the burner top and furnace inside the trailer. What would you use, protected/shielded rubber hose or a metal line?
let me know your thoughts
thanks
Chris
I am trying to get my propane side of the trailer figured out. I have my 2 tank regulator and now I need to know what you guys would plumb the propane line with. I do not have a long way to go inside. Maybe 4 feet from the tongue/tanks to the burner top and furnace inside the trailer. What would you use, protected/shielded rubber hose or a metal line?
let me know your thoughts
thanks
Chris