If I buy a car that use to run good but was parked for 2 years, what problems should I expect?

I am looking at buying a 1997 standard Diesel Jetta with 260,000 km. According to the owner it use to run great before they parked it and left it for 2 years, they moved it around through the years though. My car now is not doing great so this car is super cheap, about 1700, said it runs good now and starts good every time. Also the body needs work to pass safety apparently. What problems should I expect from this car?