SkinEz. Plenty of large trailers are trucking down the highways with auxiliary chiller units running all the way... all powered by small diesel motors. So long as its well vented it wont be a problem. I would suggest looking at an ONAN ... plenty of cheaper/lighter units around but they will give a lifetime of reliable use. You might even be able to get a cheap unit from a bus/trailer/truck wrecker. One of mates imported a school bus an it had one on board to power the heater fans ... useless for us as we run 240V but it was surprising where these things are.
Muzza .... back in N.Z. now.