I thought about converting my CNG Seaward stove/oven to propane because the only place I can get CNG gas is an hour and a half from my house. And its really expensive ($50/tank). I found a source for some of the parts after a long search but the supplier gets his parts by cannibalizing older units and the cost turned out to be prohibitive.
So instead, I'm staying with the CNG system and am in the process of building an adaptor that can fill tanks from stations that supply vehicles. The closest one is 20 minutes away. The cost of parts is about $150 and I can now fill my tanks for a couple bucks each.
Plans:
http://cruisersnet.net/a-homemade-solut ... as-aboard/