Hi! First of all, thank you for developing this mod for the community!

Now I'm playing vanilla to get steam achievements, but I want to set other planets in my savedata as "railway world" (far but big mining area) after the game has already begun.
That means everytime I explore a new planet, I have to turn this mod on → change the map settings on that surface → turn this mod off.
Is there anyway to do this in one time before I really explore them?

There isn't a way. The template used when creating new planets is read-only, and mods and script can't change it. I don't think there's any way to change it. A planet can be reconfigured once it exists, but you have to do it every time. You can't edit the template except when creating a brand new map.

Oh, I don't know if you knew this part, but you can edit a planet as soon as the space platform hovers over it. You don't have to generate chunks / map on the planet. But still you have to edit each planet individually.

Oh, I don't know if you knew this part, but you can edit a planet as soon as the space platform hovers over it. You don't have to generate chunks / map on the planet. But still you have to edit each planet individually.

That's good news for me. Thank you! I'd try it.