Oh, you're using RMXP? Then the sprites I linked you to earlier will need editing to work.
As for the World Map, what's it like in FFI/II? Is it a map you move around on, and then enter places from it, a map shown on the menu, or a map in the corner of the screen to show you where you are?
Just make a very big map, called World map, have your world plotted out on it. Wherever you have the picture for a building, or whatever, then have an event that teleports the hero to the town map when they step on it.
If you need help with the code, I'll open up RMXP and have a nosey.