Somewhere I posted a lot of things to look for (do a search), but here are some things to look for..... If they dont provide a carfax, say forget it....... I have a feeling they will change their mind.....
BEFORE YOU DRIVE
Just walk around and look at it...... if the body panels dont line up, that means that it was wrecked and it was fixed cheaply...... Check the tires.......
Open the hood, and check the oil..... The oil level will be easier to read when its cold....... It should be a golden color, and if its black, then that means it could be neglected....... Open the cap on the radiator, and make sure that the coolant is a clear, green color (if its before 96, otherwise it will be an orange)...... A lot can be told by looking at simple things.... A good thing to check (and should be reflective of its maintenance) would be the air filter..... If its fairly clean (just normal dirt, and not too bad), ie not huge gobs of gooey stuff, then it was probably maintained fine..... If its nasty, walk away...... If people arent going to bother replacing the $4 air filter, chances are they arent going to do anything else........
Driving- Make sure you try the radio, but leave it off for the drive...... Make sure that it gets to operating temp, but doesnt get too hot, and doest stay too cold (northstars run over 200, about 220 to be exact)..... Make sure the transmission shifts smoothly...... Be sure to try ALL buttons, switches, knobs, etc......
WHEN YOU ARE DONE
Leave the engine running, and pull the dipstick to the tranny fluid....... The fluid should be pink, and should not have any sort of burnt smell, or any little fragments in it...... Turn off the car, and make sure there is not any sort of burning smell just after it was shut off...... Get under the car (if you can) and make sure there is nothing leaking (except the AC water), and turn the steering wheel to each side all the way, and make sure the CV boots arent cracked........
There is more, but that should give you a start.....