FYI, natural-gas systems have tanks that have nowhere near the range of propane (because natural-gas is not readily liquified, it needs to be -256 degrees F to liquify, taking unbelievable energy and money). Also natural-gas tanks are pressurized to somewhere in the neighborhood of 3000psi (I think propane is 250 max and thats at relief). Even if you could take sweet gas (I pray its not sour) from your backyard well it can be very unstable. Is it processed or raw? Has a gas analysis been done on the well? What is its composition? Not to mention the gas well can easily change over time. Natural gas has many other components in it..... even after process (sulfer, mercury, carbon dioxide, and water just to name a couple, and all can be in varying amounts). Not to try and scare anybody but, the gas could easily destroy your engine or even harm you. So after all that, if you want greater range, safety, and inexpensive, go propane. Remember, I think propane has an octane rating of around 104 so some compression is in order. That was the earlier propane conversions down fall. People converted there 80s low compression engines to propane/dual fuel and had no power on propane giving it a bad name. An engine needs to be optimized for the fuel it is using.....even if its wood......Imagine the torque of a steam engine on the trails, who needs gears.