Agreed:
- Unlike most of Equestria, plants grow by themselves, animals look after themselves, and the weather is outside pony control.
- The Everfree Forest is near Ponyville.
- The Everfree Forest is home to the Castle of the Two Sisters, which is the former capital of Equestria.

This is some of my headcanon for a story I'm working on. It does not have the "agreed" status above, but enough people start using it, and it works its way into a few stories, some of it might get migrated up there!

- Long ago, when the Castle of the Two Sisters was still inhabited by the regal sisters, the castle was surrounded by a small town called Reverie, which there are very few traces of left today.
- The castle and town were surrounded by a much tamer forest called the Reverie Forest.
- After Nightmare Moon's banishment, Celestia found that the castle held too many painful memories, and moved the capital to the nearby unicorn settlement of Canterlot.
- The town was abandoned, and without a settlement of magical ponies, the forest grew wild.
- Over generations of ponies, the name of the forest was corrupted to the Everfree Forest.

4242442 I'll use my human version for this.

Forest is still known for crazy things, but instead of what the show goes, the forest is said to be haunted.
It is still near Ponyville
Castle was not owned by Celestia and Luna, but by their ancestors. It was eventually under siege by the armies of the former Dragon Empire (not what you're thinking) and the family was forced to retreat to a small settlement at the base of a mountain which eventually became Canterlot. What saved Equestria from being conquered was a massive Civil War in the Dragon Empire. Castle remained in ruins centuries later when Imperial and Equestrian forces raided the castle to free group of prisoners.

Still part of canon being in there but a little of my own HC there as well.