Ok, here's the update on my weekend roadtrip to Dallas from Houston(250 miles each way). The LR3 was packed with a big suitcase, a baby swing, a duffle bag with baby clothes, a folded up crib(co sleeper for baby), so the cargo wasn't too heavy, we do have the 3rd row seats(folded down).
On the way there weather was decent no rain(about 55-60 degrees F) fairly mild to moderate traffic, I averaged about 75-80mph. In the beginning, the LR3 actually made it up to about 18.0mpg until we hit some stop and go traffic for about 5 miles or so and the MPG dropped to about 17.6-17.8 mpg and the LR3 hovered around that MPG the rest of the way to Dallas. I noticed that when I actually got the LR3 up to about 85-90 the MPG went down to about 17.2-17.4 mpg. Leaving the house with a full tank by the time we got to Dallas and to the house we had about a little less then 1/4 of a tank. I think it's not bad for the LR3 but I don't know if I were to have driven at around 65-70 mph if the MPG would have been at 18 or higher or not.
Ok, on the return trip was a little different. Weather was about the same maybe a little hotter(sun finally came out about mid 70's to high 70's) Speed wise I kept it about the same 75-80mph but this time on the way back, there was a pretty strong head wind and you could feel the LR3 working a little harder(had to actually work at keeping the car straight with the wind blowing), the LR3 averaged about 16.5 mpg, only until we were about 60 miles from Houston that the wind died down and the MPG actually went up to about 17.2 mpg.
Comfort: i'm 5'8" 220lbs and the only thing that was different from my other cars(Mercedes ML 430 and C320) the seat cushion was kind of stiff on the LR3 and my butt did start to hurt a little towards the end of each drive.
All in all our first road trip in the LR3 was good, no major complaints. Noise was minimal, solid SUV. Total mileage is about 1850 miles. Hope this is informative.
Tommy