DH has a Patrol which is diesel, I've never driven it as it's a manual. I have a Pajero which is also diesel, can get about 800km to a tank depending on what kind of driving I've been doing. The Patrol's back row seats fold up, my Pajero's seats get stored underneath the floor and I don't think we've ever gotten them out so can't say how comfy they are, sorry.

There are not too many places that I couldn't drive my Pajero, so feel very safe in it