I grew up without electricity so we had propane lights stoves and fridges. The fridges are very economical and last forever (well at least the old ones, ours were Servels probably made in the 40's and they still work today.) You just have to keep the burner clean and its not a bad idea to vent them outside to limit propane scum on everythying just be careful because you can mess up the draft causing them to burn wrong. Also they need to remain fairly level when in operation. As for RV fridges, the new ones are 12v 120v and propane. Basically they have a 12v heating element, 120v element and a burner. They are computer controlled and finicky and some will switch automatically, draining your batteries when you least expect it. Having said all that, a couple of solar cells, inverter, batteries and an apartment sized fridge will probably be cheaper (unless you find a cheap used fridge) and you would have power for your lights etc. For long term use, they sell (for a large amount of money) super efficient electric fridges that are specifically designed for solar systems.