In this blog, I use the example of the map in Pokemon Red in order to think about realism in the world. I use this for an example since I have recently played it, and it has impressed me. Particularly compared to my other great interest of SNES era Final Fantasy.
On the comparison, the Kanto map does not try to be the entire world. It is instead a small island, and its nearby smaller islands. This more realistic scale helps the feeling of fullness. In SNES FFs, the area that you can traverse feels larger, however they also feel rather empty; while in the PlayStation the world feels tiny.
One thing that they both have in common is an emptiness in the towns. However, I would claim that, the diversity in the towns and the lack of formula involved, keeps it feeling realistic. For example, Vermilion City has a port, a Gym and the Pokemon Fanclub.
Getting around the map is quite difficult, for example one has to go through Rock Tunnel (where the Flash HM is recommended, though not necessary), however this is only required due to the guards guarding Saffron City. This idea helps prevent dissonance and questions of how individuals generally got around by giving the solution. A similar thing is done with the Snorlax. Saying that, the exact nature of why the guards won’t let you pass and how to solve that puzzle leave things to be desired.
My great, almost only, problem with the Kanto map is the one-way separation of Pewter, Viridian, and Pallet Town. Frankly, I don’t see what this was supposed to accomplish and it feels fake. It seems implausible that nobody is the world of Kanto would want to make the reverse trip, and that nobody took the slight work that would be needed to allow that to happen.
Inb general, the non-linearity and mild backtracking the game requires makes it feel like a world that you explore rather than just something for a game. It is definitely something that I would use as an inspiration.