I see the price of 12 VDC fridges has come down significantly in the last few years. I have a pair of lifetime small and medium size ice chests that do the job well.
That said I spent some time on the cabover camper 3-way fridge. It will light but not stay burning. Long ago a took it apart and determined that the design of the thermocouple wiring drops to much voltage across the various contacts to work reliably.
Aside from modify/repair an option is to replace the old fridge with a modern 12 VDC compressor type and abandon the gas. Would need a solar setup to run it, which I'm considering anyhow. Or even another 12 VDC portable to use on the ground outside, and for trips without the camper.
Also thinking of long run, the 110 VAC rooftop AC is 20+ years old. My Honda inverter generator struggles to run it, which it didn't before. Setup still works but is loud. A 48 VDC air conditioner, decent battery setup and panels would be a nice upgrade.