On return from my 3,400 mile trip that took me through virtually every altitude and condition, I can report that the mileage that this bike gets is VERY dependent upon speed. Not temperature, tires, luggage, or any of that stuff. If I was doing 80mph on the highway I'd get 47mpg. If I was doing 60mph on the highway I'd get 55mpg. And the only area where load actually seemed to effect the milage was when I'd pass through the mountains. Then I'd get 45-47 on the way up, then as I'd be descending I'd get 80-130mpg.
Point being: you could cruise all day on this thing at 55-60mph and easily get 250 miles on a tank before the fuel light comes on. But if you insist on (like me) cruising at 70-80mph then you're only going to get 160-180 miles out of a tank when the fuel light comes on.