Joe > How far is the finish line?
There is no finish line.
Google is your friend. :)
From the excellent FAQ at the excellent web site for this event, the America’s Challenge Race for Gas Balloons (Albuquerque):
What is the America’s Challenge Gas Balloon Race? The America’s Challenge is one of two distance races for gas balloons in the world. The other is the Coupe Aéronatique Gordon Bennett, the world’s oldest air race, founded in 1906. The America’s Challenge was founded by the Albuquerque International Balloon Fiesta in 1995 to provide a consistent American venue for gas ballooning. The results of the America’s Challenge are used to determine the qualifying U.S. pilots for the next year’s Gordon Bennett.
How do you win? It’s simple: the winner is the team that flies the greatest distance (measured in Great Circle distance) from the launch point, Balloon Fiesta Park in Albuquerque, while competing within the event rules.