The KH2FM Randomizer uses the Garden of Assemblage mod as a base. This drops you straight into the Garden of Assemblage and you can choose any world to begin and tackle in any order. In the MEGA folder, you’ll find a pre-patched ISO and a pnach file for the mod to actually work. Also included, but optional, is a pnach file to disable widescreen (useful for keeping a tracker on the side).
In order for things to be randomized, a seed needs to be generated over at https://randomizer.valaxor.com/ Adjust settings to your liking and chooze CrazyCatz’s version when downloading the pnach.
Link to mod
PCSX2