In my case, I got fed up of playing games that didn't include an "auto" button, or had disabled the whole shortcuts bar.
My solution was to add
config.keymap['toggle_afm'].append("alt_K_PAGEUP")
to the gui.rpy file.
Edit: Added an override .rpy file which adds this automatically (as well as setting the default sound volumes, default text speed, switching on the dev console and developer modes and defaulting games to full screen.) My override file is attached and works with most games without having to edit the original. Obviously you may not like my preferred text speed or full screen or something... in which case, just remove those lines.
Most
* games have a gui.rpy file that starts like:
Python:
init python:
gui.init(1920, 1080)
*Works 99% of the time. I think I've come across ONE game where it didn't work for some reason and one other game that had removed the gui.rpy file completely.
I change it to:
Python:
init python:
gui.init(1920, 1080)
config.keymap['toggle_afm'].append("alt_K_PAGEUP")
In my case, I'm using ALT+PAGEUP as my toggle keys. And doing it this way means I don't need to worry about whether the quick-menu bar is shown or not. I just press my key and it toggles auto-forward on or off.
You might have to use
UnRen to get access to the gui.rpy file, so you can edit it.
I'm sure
@recreation 's solution works too.