After action report:
190.6 miles later, I filled up with 3.123 gallons.
190.6/3.123 = ~61mpg - guess the website's right!
Comes out to a little over 3 cents a mile.
This is with a combination of short-shifting (6th gear at 40mph) and ducking by putting my chest on the gas tank. I've actually started to find that comfortable. This is also with engine braking. I think I'll continue to duck, but I've already opened her up to 12K+ on the tach.