Thanks...I'm learning every time we take another trip.

Craig

If you use the fridge on battery it consumes about 10-11 amps so be sure your tow vehicle is effectively charging the trailer or you will discharge the trailer battery quickly. And remember to change over to propane as soon as you get to camp. 

If you run the fridge on propane while travelling there are some tunnels and bridges where you have to shut the propane off. Most are along the east coast. 

Other than those two issues its really a choice based on your personal view of what is safe and convenient. 

Re effectiveness of the fridge, since it uses an absorption refrigeration cycle, it requires a heat source to operate, and that source needs to be hot to work well.  The general experience is that it is somewhat less effective when used on 12Vdc  because that source puts out the least heat.  The propane and 120Vac are roughly similar when operating correctly so the fridge is most effective on either of those two settings. But most folks find the fridge stays cool enough on 12Vdc while travelling.

Don't put a lot of warm stuff in the fridge, turn it on, and expect it to immediately cool things down, especially liquids. Think of it as more of a cool maintainer than a cooler-downer. When stocking for a trip, turn it on the the day before you leave and cool down your food in your household fridge first. While restocking when travelling, try to buy your liquids already cold for the same reason. You can also get a secondary cooler or portable 12V fridge for cooling liquids.  

Keep the fridge heat exchangers clean and the gas flue clear of obstructions, Some folks have added small fans to improve cooling performance, especially if they often camp in hot conditions,  if you do a search on the forum you'll find lots of posts on that. 

Be careful, at very cold settings, you do run the risk of slightly freezing things in the fridge section.  It takes some time to play with the settings.

They covered the traveling part, but as far as optimum efficiency in normal camping mode, installing a 12v fan in the top fridge vent will really help remove condenser heat. This will lessen the 'load' on the cooling unit and conserve propane.

Oh, and always make sure the camper is level when camped. I installed small bubble levels to help with this.

New Jersey has a restriction on open propane cylinders, but then NJ has some weird regs, you can't pump your own fuel there either.

But I hadn't heard of that in NY.  I wonder if its new? 

BTW, you'd most likely be OK for 8 hours with the fridge off if you started out with it cold and kept the door closed. 

The most I could find about it is this:

LP gas is prohibited between Manhattan and Jersey City in the Holland Tunnel. Between Manhattan and Fort Lee, New Jersey lower level of the George Washington Bridge (I-95 South) and the George Washington Bridge Expressway between Manhattan and Weehawken, New Jersey: Lincoln Tunnel. LP gas is prohibited between Manhattan and Brooklyn on the Brooklyn Battery Tunnel and between Manhattan and Queens on the Queens Midtown Tunnel.

Other than that, I have not seen any restrictions on propane use on highways in New York State. It makes sense in tunnels that go under rivers since propane is heavier than air and would collect at the bottom of tunnels. It does not make sense on wide-open highways to prohibit propane use. That would mean that there could be no propane powered vehicles either.