Not sure how different your car's drivetrain is from the next gen Camry, but my parents had a 2002 (and now a 2005) I4 that was a surprisingly good highway MPG machine:
Thread:
Speed vs. MPG chart: 2002 Toyota Camry 2.4 auto (impressive highway MPG sleeper car?)
Note though the gauge that got me the above numbers was later calibrated against a similar car - they were about 10% high. Still very decent though.
The 2002 Camry drag coefficient is supposedly 0.28. That's decent.