Work, run-around car for you or a 'family' car/van like the Astro?
Just some of the things I look at.....are there any oil/grease stains under where it's parked? Does the engine run 'diffrently' after it warms up and you've driven it for a few minuets (test drive)?
Edmunds.com is a good place to go to look at auto reviews, gas mileage, safty ratings, etc. from whatever year and make, model that you look at.