The true meaning of agoraphobia is a fear of unfamiliar environments or areas where the sufferer has little control over, such as a crowded place. To an extent, this also applies to open spaces as the sufferer will have little control over what happens in such a large space.
Frasier says, "My morning's travails aside, Niles..." after telling Niles about his show and his encounter with Willa. This is suggesting that his show was in the morning, but it is in the afternoon from 2-5pm.
Estelle Parsons, who plays Opal in this episode, played Laurie Metcalf's mother in the popular long-running series Roseanne. Laurie Metcalf played Nanny G in the previous episode of Frasier, Caught in the Act.
Helen Mirren becomes the show's final guest caller in this episode.
Title: Coots and Ladders
The episode's title refers to the popular children's board game Chutes & Ladders.