Not much to show in the way of interim photos.  We used 1/2" black iron pipe to deliver the propane from the tanks to the points-of-use.  The pipe runs down the driver's side of the bus, between the 2 middle rub rails.<br />
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Why on the outside?  Simplicity of design, ease of installation and inspection, and convenient location of shut-off valves.  We used pipe hangers near the joints and every 2-3 feet in the middle of the longer pipe runs.