I am meeting with some success. I have an ultragauge system installed. Today I drove home with my stuff. Left the trailer. I reset the gauge when I left. My gauge read 29.1mpg when I turned off of the the 4 lane 180 miles later.
I have my grill block in place and my molded front wheel skirts. About half of this tank was driven without any aero aids as I was working on my grill cover and carbon front wheel guards. With the grill block out and full air being admitted I have seen 210 as the thermostat opened. The stock temp gauge is pretty useless as it just stays in the middle.
here is my mini van as it looks today, with fresh spay paint from yesterday.
My front wheel skirts are there but are difficult to see unless you look at the higher resolution image.