Originating from TWA's hub makes it difficult because fares are usually higher and you don't get the connector miles which are 750 or 1,000 depending on your status. I used ORD-Kansas City and ORD-Louisville for mileage runs in the past with great success. You have to watch for sales in these markets but you can sometimes pick up some really cheap tickets, especially in the ORD-Kansas City market.
I think your best bet would be to somehow figure out how to get to Kansas City to originate trips. It costs as much or more to fly STL-ORD as it does Kansas City-ORD where you get twice the mileage.
Another option is to fly STL-London or Paris but this usually pays off only if you fly in the winter when fares are cheap. Good Luck.
[This message has been edited by Paul3456 (edited 07-09-2000).]