...and let's include those who traveled for the postponed/cancelled shows.
For me, it was New Orleans to London for the Wembley Arena show in August of '03, about 4400 miles or 7100 km. I was lucky to be treated to one of the best shows ever. Absolutely worth the trip.
For the record, the shortest trip for me was about a mile and a half from my flat to the Superdome.