I bring up the map of harmony because for the writers, it worked as a very comfortable plot device that has its roots on "destiny". You don´t know what drives that map to indicate these new places (although the tree of harmony introduces itself in the form of Twilight in What Lies Beneath and Uprooted) but it has been the excuse used for the writers in order to expand the map, focusing on worldbuilding and lore of these new locations.
Just place the cutie marks for the characters needed for that plot and things will go as intended after a little introduction of one minute or two in order to solve a friendship problem. In this season, the map showed three new locations: Mt. Aris/Seaquestria in Surf and Or Turf for the CMC, the Kirin´s village in Sounds of Silence for AJ and FS; and Sire´s Hollow in The Parent Map for Star Light and...Sunburst.

This is the theory, the selected characters are supposed to solve a friendship problem in this episode yet it´s not until now in which I have realized that the title of this episode actually describes the entire subversion of the map.

That is to say, what I mean to correlate with the map of friendship with this episode is that in these 22 minutes.....the writers are actually subverting and mocking at the purpose of the map. Think about it for a second.

Sunburst and Star Light aren´t solving a friendship problem but one related to their parents. The map actually warns them for forcing them to do a visit to their old town just to say that they have grown up and the problem relies on the cringe and the embarrassing moments that get out of their nerves coming from their parents (which by the way are the most comical parts all the way through the episode, I must say. Their reactions are priceless whenever they feel treated like little children). In fact, the viewer believes that in the 3rd minute, both Star Light and Sunburst say this in the train:

>SG:It's not that I don't want to go home. It's just that whenever I do, my dad treats me like a filly. Like nothing's changed since I was a foal.
<SB: Huh.
>SG: I know. I'm a horrible daughter.
<SB: N-No, no! My mom actually does kind of the same thing.
>SG: Really?
<SB: I don't even have to go home. She sends me letters constantly asking about my plans for the future. "You're a grown-up pony, Sunburst! You need a plan!"I haven't been home in a while either.
>SG: Hmph. We'll just have to explain to our parents that we're on an important friendship mission so they can't bother us.