This script is pretty much a debug tool. I made it because I wanted to know what the region ID of a particular tile was, but it was too much work to print it out.
So I decide to draw it out... Download
Get it at Hime Works
You will need this spritesheet. Usage
Download the regionID spritesheet and place it in your Graphics/System folder.
You can change region ID's for a given (x, y) position using a script call
change_region_id(x, y, regionID)
You can enable/disable the region map using a script call
$game_system.region_map_disabled = true/false