Buy a car, don't be sold a car. Try to buy a car from its original owner not some old dog that's had multiple owners, the last three of which didn't maintain it.
You're looking for a twenty five year old car so look for elderly owners.
If I were you I'd look at ebay only as a price guide, then I'd read the Chicago papers for a for sale by owner car being sold by a retiree or widow. Be patient, it's optional. If you know of some upscale retirement communities try to post a flyer in their mail room - lots of people have cars but no longer drive much and don't want the bother of selling their car so it stays and stays. Your flyer is their opportunity to act.
And distance doesn't lend enchantment - when it comes to cars; buy nearby, not in Florida or Arizona or California just to name some "enchantment". This old car will cost you between $1000 and $2500 depending on its condition so finding taking a old car on a big road trip may become an expensive "adventure".