map titles

You would have to switch the tiles graphics in the ROM and make sure everything is replaced in the right order, like as an example, the WOB right corner of a forest tile switched with his WOR equivalent. You could do this process with all the tiles (not the tiles of the map but the tiles of the tileset). I think the map data is compressed graphics so if it's the case you'll need to decompress them with PeerSpriteViewer first and recompress them in the ROM afterward. There is probably an easier way to do it too by changing some code, but then you need to know a bit of ASM. You can find the tilesets offsets in a ROM map.