Coding a 2D JRPG?

How does the game store field maps and event scripts? Separately, or mixed together?

They are mixed up in same banks but using different event commands (i.e. same opcode does 2 different things depending of the "event mode")

So should a clone follow FF6 exactly, or go with an easier to expand route that uses more space (which is cheap these days)?

There's a bunch of thing I would improve in a FF6 clone made for PC. One would be allowing event triggers and resizable entrances on world maps. Treating the world map like other maps could be an idea too, but FF6 does it partially for some things. I think the approach of making the world maps "as any other map" need more investigation to factor everything involved.