Hi all! I would like to make a quick intro then add to this discussion. While I don't currently own an RV, I do co-own a small horse farm. As such, I pull both horse and equipment trailers. I drove commercially for ~12 years, went to school, worked in high tech for 20 years until my work went to China and have been back at commercial driving for over 2 years again. Currently laid up and off of work, I started cruising the RV boards and found this one interesting. I would like to add my two cents on occasion especially on touchy subjects like this one.
Horse haulers are going through these same problems. If you looked up the drag racing link, imagine leaving live animals cramped in a box along the road. Fortunately, these incidents don't happen that often but indeed they do happen.
Along with the med card, etc., suppose that you had a radar detector on the dash? Had a drink? Your allowable BAC is only .02 and don't have any alcoholic beverage in the vehicle.
RV's, trailers for different applications, etc. is one murky subject for sure. Generally speaking though if legal in your home state, you are legal elsewhere to a point. Your rig must conform to applicable DOT regs as in lighting, tire size, rating, wear, and your air brakes must be adjusted to be within spec, commercial or not. Commercial or not, you must adhere to each state's weight(see next paragraph)and length laws.
http://www.hitchemup.com/statetowinglaws.htm
In the case of hauling vehicles, equipment, etc., securement regs can be enforced.
One area the car/equipment hauler trailer pullers, commercial or not get in trouble with is being overweight. For example, lets say the 10k licensed trailer you are pulling along with your rig is legal in combination in that the trailer axle(s) are within spec but close to the max allowable. An officer could direct you to seperate the tow vehicle and perhaps your trailer including tongue weight is now over 10k.