Is is rugged?
The 4Runner has a softer suspension than a truck so it's a nice ride off road.
I haven't taken mine rock stepping if that is what you mean. But it's pleanty rugged for getting to and from remote fishing lakes and hang gliding sites. I wouldn't use one to break trail but it's fine if it looks like there at least used to be a road there. ;-)
If you want to break trail, get a Land Cruiser.
BTW: What kind of mileage are you looking for?
My 4Runner with the V8 gets about 21mpg on the highway at 65-70mph.
You say you're coming off an 8 passenger vehicle...the 4 Runner seats 5 comfortably. If you want more, go to a Sequoia