89 Dakota 3.9 2WD. When I replaced my rack and pinion, I did an at home toe adjustment. Now I have a very pronounced neg camber. What gives?

My guess is you have the toe incorrectly adjusted. A toe out in the front will pull the control arms outward and the slightly worn rubber control arm bushings will show up as they are stressed.
Reset the toe, and the camber may return to somewhat normal.

I replaced a worn out tie rod end on my wife's PT, I had the tie rod turned in 1 rotation too far, and the steering was really goofy, it also had a lot of camber, and actually started scuffing the tires with a couple of weeks. Gene

Really can't see what one would do to the other? Toe is toe, front of tire in or out. Camber top of tire in or out.

Exactly the reason when you do a caster sweep and the toe is way out the machine will suggest you adjust the toe and resweep the caster. It all is connected! Take it to a shop that has a fairly new alignment machine and let them align it properly.Toe affects camber and caster. Just like a worn tire or low tire pressure.

You must not be familiar with the mechanicals of front suspension and steering.

If the front wheels are toe-out, the pressure can often place drag on the inner edges of the tires and cause the front to squat, causing negative camber.

Conversely, if the wheels are toe-IN, the outside edges of the tires see more tension and the car may rise while having POSitive camber.

I've run the string method and can't really see gaps. I've marked the center of the tires in the front, measured, and rolled them to the back and measured. If you get a difference in measurement, how do you know which tire to adjust for toe??

Center the steering wheel and see if one tire is pointing off center. That will be the side to adjust.