Good luck but you're stupid if you ride out a category 4 in an RV. Straight up Darin award.
Pressure is calculated at the square of the winds speed. Just because you can do 70 in your trailer in a controlled environment like the highway is in no way similar to a category 1 much less a category 3 or 4 with shifting winds and huge gusts. The increase is exponentially dangerous as it rises the numbers get bigger, faster.
Good luck you better hope it misses you.