At the end of September, director Jon Favreau escaped his "Iron Man 2" edit bay and took a couple of days for an island getaway, traveling thousands of miles to the remote Pacific island of Bora Bora to promote his comedy "Couples Retreat." But as he soaked up the sun and kicked back with co-star Vince Vaughn, his mind was still very much on Robert Downey Jr.'s Tony Stark and how the sequel to one of the biggest movies of last year was coming together.