I don't know much about the '97 Cavalier, what size fuel tank does it have? Also, what kind of driving? Freeway? Country road? City? Based on what I do know I'd say you can as long as it's not city driving.
To Hans: What kind of car doesn't suck balls? Personally, I actually prefer American over Japanese or British, but I think German beats them all, specifically Mercedes and BMW.
The key word is Should... and you should not have a problem if it is currently in a fine condition.
Make sure your engin oil is in good shape.
Make sure your engin is in good shape... no clicking and clacking.
Is the exost smoke bluish or blackish ?
Make sure that when you do 1 hour highway drives, the temperature of the engine doesnt skyrocket.
If manual, how is the clutch
If automatic, does it feel normal or iffy.
Most cars Should be able to do 12 hours just fine as long as you aren't saying 12 hours of redligning.
I don't think you'll have a problem if your mechanic says it's ok. If it's mechanically sound with good fluids and properly inflated tires, there's no reason why it wouldn't make it through 12 hours of driving.
I do suggest you take many breaks and take walks during that whole drive, it can really be hard on your body and mind.
On the subject of red lining the engine, a few times a year, I do take my car (180000KM) to the race track and do 8x30 minute sessions in one day, during those 30 minute sessions, the car is always at peak performance IE redline of the engine. Still runs great!
12 hours expressway? no issue Its likely the 2.2ltr. Only real issues are timing chain tensioner, if it sounds like a handfull of pennies in a dryer don't do it otherwise at highway speeds the motor is loafing along at about 15-20 hp to overcome aero and mech drag