When you enter the Hudson Theater, it looks almost as if we’ve turned up for rehearsal. Instead of a set, the seating includes several risers onstage, and the front of the stage itself has been replaced with a broad set of stairs down into the orchestra. The usual preshow scrum has an extra, agitating element in it. Dashing up and down the stairs, collaring theatergoers in the aisles, then rushing back to consult with various assistant director or stage manager types is a guy in sneakers and a violet sweatshirt, his short beard pointing vigorously and persuasively at anyone he waylays.