Somewhat similar but different at the same time I probably will be doing segment runs since my only hope of qualifying again for Chairman's Preferred will probably be segments. What I do is look for two small airports that are geographically close to two hubs both carrying Southwest.

This works in the case of CLE and BWI, so I can often go CLE-PIT-PHL-BWI-PHL-PIT-CLE for $60 R/T. (10 bucks a segment) with only 1 night stay required (BWI Airport Marriott rewards points)

I also often use Travelocity's Best Fare Finder and plug in random airports which have other airports close to them. I once found a fare from CAK-MDT for $40/4 segments by looking for fares PIT-PHL.

This probably works best in the Northeast with USAirways since US serves most of them and there are a lot of airports in a small amount of space, but it might work elsewhere. Good luck.