The Reverend Mother is going to Saint Thomas, one of the United States Virgin Islands (USVI) in the Caribbean Sea. It was purchased in 1917 (along with Saint John and Saint Croix) by the United States for $25 million in gold, as part of a defensive strategy to maintain control over the Caribbean and the Panama Canal during the First World War.
The title is based on the phrase "Is an ill wind that no one blows good" which dates back to the 16th century in various similar forms.
Arthur Julian (as Moon) not only appeared in this episode but also wrote three other episodes for the show (1968-1969).
The gangster's surname 'LaRue' is a French topographic name for someone who lived beside a road, track, or pathway - It literally means "the street" in French.