I would disagree with teaching them to come to the back bedroom to you. It's just like any other emergency, GET OUT. I wouldn't "drill" into my children to come to the back bedroom. What if that's actually where the flames are, and they run right into it? Fire drills are to train us how to get out now. You can make the decision on how to reach them. Practice fire drills and have a specified regroup area. That way when everyone gets out they meet at a spot clear of the motorhome and clear of danger. Make it a spot that is always away from the front end, or back end. A common direction that everyone always knows to go.