I drive cross country in my 2001 Insight (manual tranny) regularly, and average between 54 and 60 MPG across over 1700 miles per trip. This includes all manner of terrain including steep mountain passes and random hilly or flat roads.
Running 85 or 87 octane fuel depending on what is cheapest in the area. (85 is for higher altitudes)
Running Nokian RSI snow/ice tires at whatever the Tire Factory set their PSI at... I guess I should play with the tire PSI, but haven't bothered yet.
I haven't looked into the radiator block panel people talk about making yet, the car was getting plenty hot enough to auto-shut down at idle, not sure if the lean burn mode needs more than that in winter or not.
-Shawn