I wouldn't even attempt something like this with (this game in particular) all the cross event triggers.
Most likely will fault the saves doing this mid game.
Now if you do this before starting the game you wont have any worries of event trigger later in game of referencing earlier events that are now not there.
But your now visiting the realm of a massive reverse engineering of the game too remove whole subplots and events that intersect with the main plot as a whole. Wouldn't even know where to begin, let alone finding a place to park while I am visiting there.
In all honesty might be just quicker to make another game.