1990 Loyale. Changing plugs for the first time, got a new cap and rotor, but I hit a snag getting the old rotor out...seems to have a guide screw to remove and it wasn't moving and I was worried about stripping it. Is there a special tool or method I should know?

Eat more cherios,  lift weights,  etc.

That screw is prone to loosen .... so previous owner probably used some loctite to keep it in there.    Make sure you have the proper screwdriver ... #1 , #2 etc. of good steel quality.

Sometimes helps to vocalize a primal grunt when applying maximum pressure.

good luck ... and don't strip the head.