My daily commute is 66 miles each way, from Riverside county to central San Diego. It's all mountainous and hilly crappily paved freeway, and i'm typically rolling at 75-80 MPH. I'm pretty happy to say after seeing so many other posts of low mileage at high speed that my '07 Touring consistently gets me 40-42 considering how I pound on it.
I just went to Hayward from Orange County (CA) and back, and my mileage was at ~40+mpg traveling at speeds of ~70-80mph with very few other cars in the road. IME, if there are other vehicles that will bump up a few mpg at the same speeds due reduced aero drag from their wake. I about twenty minutes behind a tractor-trailer at 65mph and that bumped my mileage up to ~60mpg.
