My truck has a mild lift, slightly larger tires and some extra weight due to sliders, dual batteries, etc. I am the original owner and the 4Runner has a little over 80K miles
I generally run Arco Regular unleaded. It pays to switch off cruise control in hilly areas. It is too agressive when downshifting.
I have a ScanGuage II that helps me to manage MPGs while driving. The Toyota MPG gauge on the dash is a bit optimisitic so I have a notebook with corrected ODO miles and gas into the tank.
If there is nothing up on the roof rack I've driven from Las Vegas to Orange County SoCal and achieved 20 MPG using cruise control.
Around town the worst is 16 MPG if I lead foot too much. Average is more like 17 and best is 18.