[Jerr G] Don't know about Roadtrek,but I have driven 2ea class Bs and now have a Coach House( another class B equilent to Roadtrek) have driven a jillion miles or so with no stability problems. The secret is in the tires and tire pressure. Make sure tires are rated for the total load plus a safety margin and inflate to max pressure as on the tire. They build these coaches usually to max GVWR before you ever load you,your gear and fluids. This puts you overweight. The side wall S/B at least 8 ply.
[gdauth] Your kidding! If the coach is over GVWR from the factory, it is not safe to drive. The tire solution that you suggest will not solve the problem of being overweight. In fact if you are in an accident with an overweight vehicle you can be in big trouble, regardless of what you do with the tires. If what you say is true then NHTSA should take action against the manufactures.