I realised something not to long ago that I found interesting.
As we all know by now, before Luna's fall they lived in the castle now situated in the Everfree forest. What I find interesting is instead of rebuilding the castle Celestia abandoned it and built a new kingdom atop one of, if not thee highest mountain in Equestria in what seems to me to be an attempt to be as close to her banished sister as possible.
The Everfree Forest probably came to be due to Ponies avoiding the old kingdom in a desperate attempt to forget the suffering they experienced and probably passed this caution to their children which was passed down the generations eventually creating a natural fear of the place. Then due to constant neglect the weather formed by itself due to no Pegasus wanting to go near the place and the forest eventually over run the old kingdom. Due to it's long term abandonment plants, animals and predators began to thrive with nothing to hinder their natural progress eventually given birth to a truly dangerous location.
The name Everfree was probably given to it by the Princess upon recognising the fact that it was truly free from Pony hooves and would most likely remain that way forever more.
Just some thoughts that occurred to me. Don't need to take them serious if you wish.