75 Duster Neutral Safety Switch... I need to replace it!

If available (and it should be), it is easy. It's on the driver's side of your trans just above the pan and to the rear of the linkage. You should have wires (taped together) running to it. Pull the cap (attached to the end of the wires), remove the old switch and replace. Note: Make sure it is the same switch and look at the # of prongs on it.