So, I am wondering the same thing. I think OP was not really asking MAY I, but CAN I…
Understood other's objections, passing on the advise some will.
Dangers with propane, yes, that is a given, same as gasoline. I should be able to find all about combustion on the web.
To drive with these HiLos and run the propane on gas is the issue.
Has anyone made a modification to vent the gases and keep them out of the cabin?
A fan like this
https://www.amazon.com/Ventline-VP-...=1508123409&sr=8-2&keywords=round+rv+vent+fan
should be powerful enough to pull all the gases, and all the other air, out.
This could be mounted on the upper side above the side vents. It could be run while driving, or maybe just when parked and running fridge with roof down.
Turning the fridge off is not an option, it will not keep cold on my long drives through the hot summer. Battery is not an option, not with my batteries, that will destroy them pretty quick. My batteries are something I want to make last longer, not shorter.
I was thinking of a mod where I can open ports and connect top of fridge cabinet to a hole in the roof for the fan, making it air tight from the cabin, but open to the outside, then having something to seal it back off when raised, but I would rather do something more simple.