It is a Forest like area. Fazbear hills is also the first location you start at in fnaf world. Fazbear Hills is also home to Desk Man, DeeDee, and Mendo.
In Version 1.1 The Desk man talks to you if you keep walking to the house.
In Version 1.2 The Desk man talks to you again but this time if you beaten the game Fredbear would appear outside the house and send you the Backstage of The FNAF 4 Halloween Update.
Another Easter Egg is that on one of the Trees in the overworld if you keep walking to it it will open a path to the Halloween Update Backstage near Purple Guy and the Graveyard.