Missing brake return spring could easily never be noticed if you never use cruise control and don't have an electrically controlled transmission (like you don't). In the first case, going over a bump could cause the the CC to disengage, and in the second could (this has come up) cause the torque converter to unlock momentarily.
I got it reinstalled. It actually connects to a little groove on the retaining pin for the brake pedal, then the other end hooks into a hole in the bracket up near the pivot point of the pedal bar. It's apparent once you realize that the springs hooks onto the pin.
Don't really wheel it, rather I use it for camping with my son's Boy Scout troop and hunting. I have friends with ranch land that requires 4x4 in areas, so I get me fill that way. Mainly I use it as a hobby to work on and tool around town. Turning wrenches is therapeutic...when I have time.