[outwest]

Read awhile back on another forum about a person that left either water heater on gas mode or furnace on (forget which), got flagged down by another motorist, saw flames coming out of side of trailer in mirror, and had to pull over and put out the fire.

That being said, there's been a time or two I've accidentally left furnace on for travel and nothing bad happened. And I always leave fridge on in gas mode for travel (tow vehicle is diesel and use pump islands for semi trucks, so nowhere near gasoline pumps). But as far as heat I'd probably simply turn the heat up a little before travel and turn it off when leave since only gonna be 6 hour in cold. If you stop at a rest stop can always turn heat on for a bit. Plus, the sun on the trailer will help keep it above freezing (assuming it's not overcast).