Having lived in tornado territory all my life, I can say we never altered our plans to do anything or go anywhere. Those storms are so darn unpredictable there is just no telling when you might run into problems or not. Best advice, be aware of your surroundings, keep a good weather radio, and know where the safest place is to go in the event of a problem.
I would always opt for safety. Watch the weather. . .if you see something coming up, avoid it. One year we were headed across Ohio to family in Indiana. Storms all around us. We had the weather radar up on the laptop with our navigation. We snaked around the roads and highways avoiding the most dangerous cells. Made it fine.
Dale