Diesel is def the way to go. Not only more kms to a tank, but in the western states diesel is cheaper than petrol. The longer range & cheaper prices do come in handy over here. My parents have a 94 Landcruiser Troop Carrier & use around the same in $$ as I do in a 05 V6 station wagon. We did WA - NSW together, both towing caravan's & fuel costs were very similar.

Patrol & Cruiser are top of the line for off road. Pajero, Hilux, Navara etc come in after them. They're the tougher cars made for hard driving. Not sure how good a Kluger/Territory etc would be & not sure they're available in diesel either.

Joining forums is a good idea. And with 4x4's, you do get what you pay for. That's why the Patrol's & Cruisers hold their value so well.