Here is yet another guessing game for the next Equestria Girls movie, Legend of Everfree.
This is my guess:
With the pictures of Twilight's room posted online and how she looks sleepy on the bus in the trailer, she need this trip after working so hard.
The farmers in the story of Gaia Everfree look alot like the new characters Gloriosa Daisy and Timber Spruce. Either they're brother and sister, they are descendants to the farmers, or they only look like that cause they're tell the story.
I believe the crystal caves are enhance the Humane 7's magic. It's possible there are part of the human world that are connected to Equestria, other than the portal at Canterlot High.
As for Gaia Everfree, I too think she was banished there from Equestria. For my thought on her character, she could extremely unique other than just another monster. It would be interest if she could become an idealist villain. I might be a eco-extremist trying to protect her forest by any violent means. And for what reason does she have for attacking the camp now of all times. It might have something to do with the Humane 7 and their changing magical abilities.
Gloriosa's character profile said she was hiding something under her cheerful smile. This implies that she could be the villain. So she may have something to do with Gaia Everfree. She could either be imprisoning and Gaia Everfree's powers, Gloriosa might be possessed by her, or she might actually be Gaia Everfree in disguised.
This is Sci-Twi first movie as a student of Canterlot High. She must be still adjusting to her place there, and struggling to live up to Princess Twilight's success. There is also the notion there will be a love triangle between Twilight, Flash Sentry, and Timber Spruce.
Please post your theories of the movie in the comments below.