If it were 5 inches you would probably have crashed by now.
Simplest way to check is to jack the car directly underneath the ball joint (without hitting tire or wheel) Grab the wheel at 3 and 9 o'clock and move side to side. You aren't trying to turn the wheel, just see how far it goes with no resistance. That will do the tie rods.
Then take a long crow bar place in under the wheel from the side of the car (perpendicular) put the tip on the ground just past the wheel and pick up on it so the middle is under the tire. If it goes up and down, it's the ball joint.
Now the reality is that the car is 30 years old and if those parts are original you probably want to replace as much as possible considering that you will need an alignment. It would suck to replace one part, align the car, then need another part a few months later.
So ball joints, tie rods, steering rack, control arm bushings and throw in struts should all be checked at one time.