In my current campaign time travel is possible. The party is on the run for a Warforged who has introduced them to the concept. They have the advantage of having a device that actually opens Time rifts who can carry them anywhere in time anywhere on Eberron. Only problem is that they need exact coordinates and they can only be found in (planar) dragon guarded locations in the prophecy. Meanwhile the warforged and his men can only travel time using a special lightning rail craft, meaning they need the rail to get to the past and back, for now anyway. They have to find travel time in order to find out who has destroyed Cyre.
Alright, sorry about the long story. Now the group has found the coordinates to get to 15,999 before Galifar, in Darghuun. They need to find coordinates to get back and I need an idea of how thing work/look around in these times. I have no idea how the guys are going to get back, but finding the new coordinates won't be easy since every era only has one or two pairs which can lead practically anywhere...
If you have any idea, please help me!
So I would say that if the party arrives during the early empire there would be many Kings ruling over their regions with conflicts happening every now and then. Also in the early days of the empire The Cold Sun lizardfolk would still be living in pockets throughout Khorvaire in regions of plains.
I the party arrives late in the Empire they would find a single Emperor ruling a large part of Khorvaire with small isolated kingdoms in the mountains and other geographically isolated areas. They could also come across the first Dwarven settlements in present day Mror Holds.