there is one road about 14 miles from the office to the liquor store in SC, its relatively flat with not too many stops and posted speed limits between 35-55 and I always get close to 80 mpg. If I found about 50 miles of similar road and just drove it for a whole tank over a day or too I bet I could get 700 miles from one tank
Half of my daily 40 mile commute is similar to this, although I do have some hills to contend with. I generally drop back a few mph as I go uphill and coast to whatever speed I can get away with on the downhill stretches. I don't think it's possible to go into EV mode over 44 mph, but the C's sweet spot definitely falls in that 35-55 range, and I usually get 70-75 mpg here. Combine that with the other 20 miles on the highway where I get 50-55 mpg at speeds from 55-70 mph, and I end up with a very nice 60 mpg average for my ride to work. It's really an amazing car.
