Hey Deano and Kate, this came up on the vandwellers construction forum yesterday. I have seen some people put the tanks straight in their van, but I am in the group that thinks that is a big no -no. Most travel trailers either have them mounted outside ( on the tounge, like mine) or in an enclosed compartment with a door to replace the tank, usually on the outside skin. Home depot sells a steel 16"x16" door with a lock mechanism in their Sheetrock department ( used to access pipes, valves, wires, etc.) for about $40. You could use this if you cut a hole in the outside skin of your van and built a box on the inside. The big thing to remember is that propane is heavier than air, that is, if it escapes, it will build up and "creep" along the ground, so a vent MUST be included down low, not up high like a fridge vent ( fridges expel warm air, which rises) . A propane detector
or " sniffer " might not be a bad idea either.
Les