>Preemptive TLDR: 11 routes roughly the size of kanto/sinnoh route 1,
>3 towns, 8 cities, 5 dungeons?
>a massive chunk of land with seemingly no purpose, no apparent victory road or elite four or pokemon league either

Now for the in depth analysis, prepare for megaautism
We actually can map every area seen in the trailer to a place on the map of Galar, and we actually get to have a pretty good look at what I think the first 2 routes of the game are.

We get a handful of scenes from various perspectives, and we can map out a good chunk of the area. IMO, each route looks roughly the same size as Kanto/Sinnoh's first route, decently sized, but the routes that we have seem to be low in number, if the size of these routes in the official artwork is anything to go by