Am doing daily commute of 140 miles, all freeway (except for about 2 miles). Have got about 70k miles on car. No maintenance issues (ever). All I've done is maintain the oil change & maintenance schedule. It's very economical to run & maintain. No special concerns.

By staying under speed limit (65) I'm averaging between 50 & 60 mpg (depending on conditions: temperature, wind, dryness/wetness of road, etc.). But if you drive aggressively your mileage will most likely go way down. On the other hand, by driving extra slow, coasting up hills (by reducing speed), etc, I've gotten many 70 mile trips between 65 & 70mpg.