I've got a Dometic RM182B that was designed for the VW Westphalia. Darn thing is stubborn to light
unless the system has been running on electricity. Pre cooling with the 120 helps, I've run it a few times on propane while travelling and only had it blow out once. My understanding is the intake and exhaust flues on this fridge
are designed for travelling while lit.
I tried 12V last trip, but the 3 guys (me, myself and I) that wired the new harness, got things mixed up on the accessory pin 7. +ve on the TV end, -ve on the trailer. A battery
fuse on the trailer saved the day, the Rangers alternater did not keep up with the fridge
I have not installed the fans yet, but putting in a baffle and moving the vents made a big difference in cooling. I posted how I did it here
which contains a link to a website on venting.
As for the legality. I know we had to take a bridge in Montreal because no propane was allowed in the tunnel under the river.