When we pull into a gas station DW gets up and goes back to turn off the refrigerator. We don't travel with the furnace or water heater on. There is no need to turn off the propane, as it's the flame at the refrigerator or the spark ignition that is the potential source of ignition. After fueling and pulling away from the pumps DW goes back and turns the refrigerator on again.
I agree with others that there is a very low risk of a running refrigerator starting a fire at a gas station. A low risk doesn't mean that it can never happen, as seen in this
link from an earlier thread on the same subject.