Re: power outlet
I haven't finalised my cargo setup and on my last trip I ran my fridge off the rear power socket. Ten days later, the fuse gave up... probably because the wiring behind the socket is very undersized for the task. The voltage losses result in a higher current draw, which tends to continue in a downward spiral.
If you don't have Quadralift there's a decent space under the front passenger seat. There's been a few fitouts detailed here, and at least one was located under the spare wheel under the car.
To be honest, the limitations have left me unenthusiastic about finishing the project... but I'll probably be using an AGM battery (or two) in the void between the rear seat back and the fridge. Two might allow better space utilisation...
It's important to be clear about your expectations regarding the temperature and duration the fridge is to be able to run, and in what ambient temperature. Only then can you determine the battery size, and where you can locate it.
2014 Overland CRD
Perth, Western Australia