On a recent trip 200 miles road trip.. I did 18.4 going and 19.1 going home.. based on the math.. every day driving around town I avg between 12 to 14.
15-18 mixed driving, 8-13 towing, max on a tank was 20mpg. It all depends on the Five W's - Who, When, Where, What For, What weight.
4.7 is comparable to a 4.0 in my Tacoma, 4.7 in a Tundra, 2.7 in my Tacoma. Thankfully it has a 23g tank, better than the Tacoma 21g, wish it had the 26.5g 1st Gen Tundra tank.
I'll chime in too since I did a recent "hyper-mile" test. This involved getting the best possible mileage I could. My commute is 60 miles round trip everyday, 98% highway. Usually I commute in the Subaru, but decide to give the 4Runner a go, in the name of science.
By only using the truck for highway commuting for a whole tank, driving no more than 60, closer to 55 when possible, drafting semi trucks, never getting the RPMs past 2500, and airing up the tires, I attained a meager 19mpg.
What I learned - driving slow is WAY more hazardous than driving fast. I'll take 15mpg and drive 75-80 any day. Hanging out in the slow lane dealing with merging vehicles and semi trucks is not fun.