Stores that sell propane and accessories sell hoses in many different lengths and most can custom make them. I've seen them in the online stores up to 20'. I think mine is 9' and is long enough to get my grill or stove as far from the trailer as I like. I would never use rubber hose for anything but the connection between the regulator and the black pipe manifold. That one is cheap and easy to replace if necessary. Rubber hose running under the trailer is subject to damage from road debris. Copper acceptable and does not need to be covered with anything for any reason other than aesthetics. If copper is used it does need to be supported about every 18' to prevent vibration and abrasion from rubbing on something. Copper will wear through quickly.