Map help

I want to have a hack to in only in the WOR world but I want to keep the character intros that are in WOB and events like the Returner's base event, any ways of how to do that?

The issue I foresee is setting all the variables that tell the game, say, what NPCs to load at what point of the game. The framework could be done relatively easily by adding Exits using the map editor, but it might take forever to troubleshoot to make sure you get the variables correct.