Keep in mind, tornadoes impact a tiny area compared to something like a hurricane, so even though there are more of them, the odds of being caught in one are slim. Sure you will see pictures of tornado damage but what you won't see is the many thousands of times more areas where a tornado didn't hit.
That doesn't mean you don't pay attention but I wouldn't panic over the idea there might be one. I would make sure you have coverage for hail. While unlikely to be dangerous, far more likely to cause damage to the RV.