I have a 1991 Passage 42 that I converted to propane in 1993. We cruised the South Pacific, and CNG was available only in NZ, while propane was available everywhere. It was time consuming, but not particularly difficult or expensive to do.The hardest part is finding a properly sized propane locker and locating it conveniently. We purchased an airtight purpose built plastic propane locker from West Marine in 1993. It has a gasketed top and a vent at the bottom. It holds two of the 11 pound (four gallon, I think) propane tanks. I truly cant remember whether it came with a double tank hose set-up or whether I bought that separately from West. In any event, that part is very easy to come by. I purchased a solenoid that was very easy to install inside of the actual propane locker. The entire locker fit in the upper starboard lazarette right where the CNG tank used to be located. I cut a small plywood board to serve as a shelf and just laid it on top of the wire support that used to hold the CNG tank. The locker is secured in place by webbed belts secured to footmans loops I affixed to the wall of the lazarette. To refill the tanks I loosen the webbed belts and let the locker fall towards the center of the lazarette, after which I can take the top off and remove the propane tanks for refilling.The bottom of the locker has a nipple for a vent hose. I ran a hose from that nipple to a hole that I drilled in the side of the lazarette, making sure that the vent hole was about one inch lower than the nipple and hose run. That ensures that the propane leaks overboard, if it leaks at all.Running the hose from the propane locker to the galley is a breeze, as you just follow the old CNG hose run. You run the solenoid control switch wires along the same route. I installed the solenoid control on the galley cabinet right above the microwave oven, where the fan switch is located on the older P42 models. I also installed two propane sniffers, one in the galley floor area and one in the bilge area, just under the freezer compressors.Your Seaward stove is easily converted to propane by purchasing their standard jet conversion package. The jet replacements are a breeze.During the years we lived aboard and used our stove/oven regularly, we found a single tank of propane would last about 8 to 12 weeks. That provided us with plenty of propane for even the longest island excursions.