Arcana is an SNES role-playing game in which just about everything is done through a menu, accessed via the A button. You know Dragon Warrior/Quest? Like that.
I think it would be convenient to map the unused controller buttons to a few of the more commonly used functions, such as the map. So instead of pressing A -> Down -> Down -> A, I could press maybe the X button and call it up immediately.
I am not expecting any specific help (you would first have to familiarize yourself with the ROM's layout, and at that point I may as well ask you to do all the work). But where would I start? Would I have to look through the ROM itself, or the memory? Are there any emulators that can step through processor instructions one at a time? Has any game been given similar hacks I can use for reference?