This documentary takes place within a loose tongue-in-cheek framework of Arthur Dent coming home to Earth. Several of the items in this framework (mail piled up behind the door, putting his babelfish into a fishbowl, etc) are borrowed from similar events in the fourth book, "So Long, and Thanks for All The Fish".
The opening sequence, which shows a spaceship approaching Earth, includes a quick glimpse of the TARDIS from Doctor Who (1963).