I'm cheating a bit, since I've driven the twinned model: 2008 Dodge Avenger
I'm assuming it has the The Chrysler/Mitsu 2.4L, which really works hard at 70 mph with a headwind. It all depends if you use the cruise control. Here are the Cruise estimates:
30 mpg highway outbound (headwind).
32 mpg highway inbound (tailwind).
16 mph avg. city in Wye-Cheetah.
Not using the cruise?
33 out, 35 back. City = N/A
The 4-speed tends to kick-down with the slightest grade. I averaged 27.5 in mixed driving with the 2006 model (pre-redesign), which tended to be a bit more efficient.
Enjoy the cooled glove box (if equipped) for sodas/water bottles. Hopefully it has Sirius Satellite Radio for that distance.
Have a good drive!
RH77