glad to see your build coming long. For propane I'd use 3/8 black pipe from the tounge to the galley under the trailer and rubber propane hose to the tank and stove. (soft copper will work harden and crack if allowed to vibrate so you have to clamp it real good. the iron is kind of self supporting so if you have a straight run its easier to mount. Just don't mix then ,you don't want a dissimilar metal thing going on.
your build is looking good
John "Gaston"
