Someone at Apple was way ahead of you. From the BASIC command prompt
type:
PR#4 <return>
control-A <return>
PR#0 <return>
This turns on the mouse and initialises it. Since you can't have a mouse
and joystick connected to the Apple IIc at the same time, the IIc will
now use the mouse as a joystick. Very quick and easy, but unfortunately
this only works with the IIc, and only works with programs which use the
firmware paddle routines, which a lot of games don't use.
Yeah, I saw that when reading thru the //c reference manual. Very
cool, but not very reusable since it only works on one model. :-)
However, for prototyping something for my own uses still very handy
(because if you DO find a program that it works with, you know to do a
memory search for a JSR to the firmware routines)