The day this episode aired, Broadcasting Magazine came out with a list of series likely to be canceled - with "Gunsmoke" heading the list even though its highest-rated episode of the year had aired the previous week. This was due to poor demographics: too many rural and overage viewers, with the younger urban viewers watching The Rookies (1972).
This episode's title is probably derived from the final stanza of Robert Frost's poem "Stopping by Woods on a Snowy Evening": "The woods are lovely, dark, and deep, / But I have promises to keep, / And miles to go before I sleep, / And miles to go before I sleep."