Some of what he is telling you is "Scare tatics"
Closing the gas line.. You go to the hardware store, You tell them the size of the connector, The man hands you a brass plug.. And you replace the Fridge with the plug, it is that simple.. No harder than re-connecting it.
OR, for added safety, you trace the line back to the manifold and remove it and use the matching plug there (Will be a different plug)..
Question: How far do you drive between power outlets (or generator runs). A residential fridge, with the door locked closed is good for at least eight hours (that is about 400 miles) so long as you have power every time you park, Either home made or commercial, you need not use an inverter.
HOWEVER many places you dont' want the genny running all night long.
Also, how much inverter and battery do you have.. A Residential fridge may need 1,000 or more to kick start it, far less running, and I'd want at least 3 or 4 pair of GC-2, And the biggest converter I can get as well (like 150 amps).
Also.. Find out what the starting power of the fridge is... If it is low enough than a Honda EU-1000i or a Yahama EF-1200i (neither of which product that much power save for a very brief amount of time) may be able to start it, (If they can start it they can run it no problem) and there are dang few places I'd not be afraid to run one of those at night. You need to do a bit of odd wiring to use one of those but I can describe how to do it if you wish.