Get a SAME capable weather radio and keep in in the camper.
Know where the shelter is (or if there even is one)
Have your "exit gear" ready
* clothing INCLUDING SHOES
* a pillow to cover your head with, a blanket just for comfort.
* first aid kit and what emergency essentials you think helpful
* any medications you take.
* identification, drivers license and your health plan card
* cell phone.
When you leave the camper, turn on exterior lights. That my be the only lights on after the storm passes if power is lost. If everyone did that there would be less chaos in the aftermath. Even if a rig is on its side the lights may be still on and helpful.
If you receive a tornado WARNING get to the shelter. On your way assume no one else got the warning and advise as many people as you can to get to the shelter (go ahead, make a fool of yourself! Loudly!)