Why though? Just do that
View attachment 4130939
-Make new Main maps folio: "Story Progress1 to 4 or v0.4 to 0.55maps or Chapter 1 to 4" (random names)
-Copy every old map to reuse in the "Story Progress1 to 4 or v0.4 to 0.55maps or Chapter 1 to 4"
-Clean the old events and just make new one in it.
-Add the new maps in them
The only big issue would be to warp to the right map but at least you don't have one event with more than 10pages of script with proper switch or variable to trigger.
Fujino put the Prologue apart, i don't get why he doesn't do that if there is to much events in one map and the way you can chose a chapter make it perfect for it.
Well, hope for the best.