Petrol GU for towing - any comments please

[monty]

Hi
Thinking long term ownership here for towing caravan.
Currently GQ 4.2 diesel (non turbo) towing Tvan. However in next year or so will sell Tvan and get dirt/off road caravan which will be around 5-700kg heavier (van not decided as yet) i.e around 2.2T ATM.
Like the GQ but will require something with more grunt for towing and to be honest I'm getting older and want a bit of refinement. I will NOT turbo the GQ.
Trips will included GRR, all around WA top end as well as Savannah Way, outback NSW and Qld. I'm sure you understand what I'm talking about.
Petrol seems to be available generally in outback, but I know diesel does give better mileage. Thinking maybe even auto box.

So please give me some opinions on 4.5 or 4.8 Petrol GU so I can decide if this would be feasible. I'm only thinking petrol as entry price lower and likewise maintenance, so this will offset the extra fuel price I guess. As long as distance between fills is do-able. I have not traveled that country up north yet.

My budget will not get close to new vehicle.
If opinion supports either 4.5 or 4.8, what should I look for when buying as it will be, what, 10-12 years old?

Any other alternatives please put forward.
Thanks folks

[threedogs]

expect around 18 per 100 ks towing on average, power to burn
thoughts on why not to turbo your motor, cheaper you already
know the 4x4 inside out,,just saying, heaps cheaper to

[monty]

Hi threedogs,
Never have wanted to turbo motor. Not factory, not wanted. That's me.
Also have to admit that I'm getting softer, so really looking for a bit of modern refinement. Yes I enjoy not having any electronic stuff, and yes I like the 'unbreakable' running gear, but finding I want a bit more now getting into my doddery years.
Could of course be tempted to other makes too, e.g. Mitsu products, but like the Nissan approach generally. Had a V8 Disco Series 1 some years back and was very very comfortable, nice turning circle etc., but LR dealer took 10 days to diagnose what turned out to be a simple electrical issue. Bush mechanic would have been quicker!