Eric - I converted our 1993 P42 to propane from CNG. (I sold the CNG tanks on the internet so I can't help you there!) I used the rear starboard locker for the propane tanks. I made my own mold out of some plastic wastepaper baskets that were the right size for the large propane tanks. Once I had the mold made, I layed it up with fiberglass and then used 3/8" plywood to divide the locker in half and then made a wall on the outer side of the locker. It was a difficult job, but it turned out real well. You also realize that you have to change the jets for propane on all the surface units as well as the oven. The pilot light on the oven seemed to be OK-so I didn't change that. There are other requirements to the conversion, like the solenoid, venting, gas line, etc. If you have any specific questions, feel free to email me. Defenders Supply has CNG tanks for sale in their catalog.