The quicksand scene is shot in the same forested area as the opening credits of the Andy Griffith Show.
Last episode of the series.
The outdoor scenes with Mark and Lorrie were filmed at Franklin Canyon Reservoir or "Myers Lake" as it's known to fans of The Andy Griffith Show.
The song Mark sang and which was used as the background music is "Greensleeves" which was the basis of the Christmas Carol "What Child Is This".