Interesting comparisons !!
Surprisingly you didn't get much better fuel mileage with the pop-up. I towed a 2720 Trailmanor with a similar truck setup (5.4L, 3.73s, F150) to yours, and averaged ~15.3 mpg in the 2 years that I had it.
Pushing all of that air out of the way digs deep into fuel mileage, regardless of the front design, although I would think the V front should help a bit. 1 of the reasons we bought our Surveyor is that it had a nice "rake" to the front end, which seemed to me would allow air to flow better.
On a 400+ trip (each way) last week, we got 9.9 mpg going, and 10.8 mpg coming back.....according to our ScanGauge II, which I have synced pretty close to the actual fuel mileage of the truck. The only difference was we did about 1/3 of the trip coming back on 2 lane roads at 55 mph instead of all 65 mpg interstate driving. Even with the multiple stop lights we encountered on the 2 lane roads, the ScanGauge indicated a 11.6 mpg at the end of that road. The rest of the trip at 65 mph dropped the overall to 10.8 mpg. Speed hurts fuel mileage !!
Chap , DW Joy, and Fur Baby Sango
2006 Ford F150 Super Cab 4x4
2008 Surveyor 263