Divided to 4 parts similar to Alola. Looks like that's how we'll be doing it in the games as well.
Sub Area 1 - Starting Towns + Wild Area + Forest
Sub Area 2 - First 3 Gyms + Wild Area
Sub Area 3 - Last 5 Gyms + Wild Area + Team Yell Hideout (Think: Po Town)
Sub Area 4 - Snowy Mountains + Climax + Wyndon (Combine Akala and LusaHideout)
Just think about it as a reversed Alola, where you start from Poni and end up in Akala.
I won't be surprised if Ultra Sword and Ultra Shield or a prequel/sequel to the story would open up any of the following:
New Gyms in "New Cities/Places"
An Expanded Wild Area
More Pokemon
North of Wyndon
Poke-Scotland
