2 way or 3 way fridge for 8-10 week trip?

hi guys

about to embark on an 8-10 week trip to northern territory. i have a camper trailer and EL falcon so 2 wheel drive territory only unfortunately for the moment.

we have not made any itinerary so we don't know whether we will be in parks with powered sites or if there is plenty of opportunity for stopping at cool places in a 2 wheel drive for a few days.

the fridge will have to sit on the back seat. i am putting a battery on the trailer with DC wiring for a small fan, fluro etc inside.

i am prepared to put a 6mm cable into the cabin of the car for 12V and am happy to wire the trailer to recharge the battery on it and to put in a deep cycle battery in it.

i just don't know whether to get a 2 way or 3 way fridge? i don't want to spend more than about $900 if i can get away with it. i've got to lift the fridge in and out of the car each night.

i understand that this might be all hypothetical if we get powered sites all the way but i'm trying to guess future use and needs from a point of complete ignorance.

i've been reading and researching and asking questions and some say to go 2 way and others say to go 3 way.

any help from people who have previously been in this dilemma would be appreciated.

ps - we are soon about to move to north qld so will envisage doing plently of weekend trips and up to 2 weeks quite often up there as well over the next few years.