Well, FlyerTalk is a great source for mileage runs.
It helps to know which cities are legal connecting points for which airlines. And, please don’t join FT
and post “Hi, I’m new, I’d like a cheap mileage run.”
Spend some time reading, playing around with Travelocity, Expedia, etc.
Understand there is a difference between a good deal and a mistake fare. I landed a $467 all-in (including taxes) round trip ORD
last Thanksgiving (no notice). That was a regular, published fare – just a really good deal.
A mistake fare is the $2.00 round-trip from many points to Watertown, NY (and other places) on US. FlyerTalkers gobbled those up by the 100s.
"Wouldn't your boss like to fly home nonstop at 4:30 on a Friday afternoon?" -Airline Exec to Congressional Staffer