To answer your question, many of us travel with the
refrigerator running on LP gas. This is not to say that some of the following posts will not agree with this, but I have done it for over 40 years and have yet to blow up anything. But, you do have to turn it off when refueling and when driving through some tunnels.
Standard trailer to vehicle wiring usually can't carry enough current to keep the
refrigerator running on 12VDC and charge the trailer
battery while traveling and you risk running down your trailers
battery rather than charging it.
Yes, it's easier to see it light off in the dark and, if your
refrigerator has that pesky push button spark
generator, it can be a real trial. I usually use a BBQ lighter and pre-heat the thermocouple for about 15 seconds before pushing the gas button and
lighting the flame.