Many of those trucks aren't legal, though, they just count on police/DOT apathy. It's a very gray area, but to be legal in all 50 states, your RV/straight truck should be less then 45' LOA, and even then in some states such as California, you may be restricted to certain roads. Truck-trailer combinations (i.e your RV towing a stacker trailer) should be less then 65' overall in order to comply with most states rules. That Saunders truck is just asking for a ticket (or to be impounded). This was an issue a couple years ago with some guys running big toterhomes for their race cars in Florida. I don't think any got impounded, but I recall that some of them had big fines.