….so all they need to do is get Ark to Resurrect the surface world’s continents….(Only Terrangima fans will get it)

well of course they’re no EoH
 
no really think about it.
 
Luna doesn’t return as Nightmare Moon, meaning Twilight never becomes friends with the rest of the mane six thinking her trip to ponyville was a huge waste of time.
 
No Magic, no friendship, no elements

Meh, that was me. Login, mumble.

There’s another border you can go to.
 
Cerberus guards it.
 

 
For a long time now, and of course it’s unlikely to ever be addressed in the show, here is my creation myth for Equestria:
 
In the beginning, there was a deep darkness. The Depth, and the Darkness, became themselves. For a long time, this was all. But then they noticed each other, which was a great surprise, and, to their surprise, rather pleasant. They began to love each other. This created Love.
 
This pleased everyone concerned, and so the Abyss, and the Dark, and Love all created new things. But creatures of love were frightened by the creatures of the emptiness and vastness, and so Eros created for them a smaller, brighter place where they could live a while. This was Equestria, the world created by Love, whose strength in the form of the Elements of Harmony continues to keep it safe.

And then the Helghast Ponies who were inadvertently abandoned there attack.