EX.I want to skip to the chapter 4 Elmdor fight.
Not really. You could theoretically manually activate the entire world map and change your story progression variable to the right value (which is not documented) once you finish Gariland, but a lot of things would be missing as they wouldn't have activated as they gradually are with the story. One of the biggest is the Ramza ch1 to ch2/3 to ch4 'transformation' which IIRC would make Ch1 Ramza leave the party after a Ch4 story fight. And no, not replaced with anything.
People typically just download saves if it comes to that. There ought to be one floating around out there that's close to that point...
Alright thanks for the suggestion