With a different twist on two propane tanks, we have the stock one on the drivers side and a spare tank mounted on the outside of the van at rear end near the engine vents.   This is 4 gallons and mounted in a holder similar to what you might see on a Jeep or overlanding trailer.  It now has a security chain also!  We purchased it from ATOverland (good folks, ask for Martyn and mention us)

The OG tank cooks our dinner every night and makes coffee every morning.  The minion tank (see photos at link please) runs a BBQ grill, gas heater and water heater for hot showers.  It is a terrific system for our van-life style.

PHOTOS-

https://slowcarfasthouse.com/2014/12/10/busquando-un-minion/

https://slowcarfasthouse.com/2015/03/10/things-are-heating-up-in-here/

Geneva Saint-Amour
www.slowcarfasthouse.com