I had, (recently sold it) a 240 volt freezer.
It was one of these basic Electrolux, freezer off Ebay for £40.00.
measured 600mm x 600mm x 600mm., so I could have it in the caravan (small width doors) or in the awning
We used it in the caravan to supplement the caravan 3 way jobbie (which was useless).
We would pack it the day before, in the house, plugged in.
When we were driving, the freezer stayed in the boot of the car.
I used it with an inverter, I think it was using 3 Amps @ 240V when running.
I had a 1000W inverter, with home made 4mm leads fused, through a relay, directly off the battery.
relay would energise from the "AUX" circuit which I got off the "ciggie". lighter.
So essentially, it only ran, while the engine was running.
To be honest, it didn't run that much of the time. The meat though was always frozen.
When we got to camp site, I lifted it out the boot, and right into the caravan awning, where we had mains hook-up.
When I get around to my "long trip" this is exactly what I will do again.