FWIW, here's the licensing requirement for Ontario...
Licence Change for Operators of Recreational Vehicles
Effective July 1, 2011, you may now tow a Recreational Vehicle (RV) weighing more than 4,600 kg with a Class “G” driver’s licence if:
•The towing vehicle is a pick-up truck equipped with the manufacturer’s original box, with a gross vehicle weight rating (GVWR) not exceeding 6,000 kg and equipped with no more than two axles and not being used for commercial purposes;
•Combined weight of pick-up truck and RV does not exceed 11,000 kg total gross weight;
•RV hitched to pick-up truck by means of a fifth wheel hitch assembly;
•Only one towed vehicle in combination;
•Pick-up truck and RV not equipped with air-brakes;
•RV (towed RV) Transport Canada compliant and manufactured to CSA Z-240 or Recreation Vehicle Industry Association (of America) standards;
•Floor space of RV is primarily living accommodations;
•Operated by holder of full class G driver licence – holders of a graduated licence in the class G1 or G2 not eligible;
•Compliant with all other Highway Traffic Act weights and dimensions requirements; and,
•No other type of towed vehicle is eligible for this proposal.
Effective July 1, 2011, Ontario now allows operators of recreational vehicles (RV) to tow RV’s on a full Class G driver’s licence if the trailer weight exceeds 4,600 kg. Previously, operators of towed RVs required a Class A licence to operate their vehicles and trailers when the trailer weight exceeded 4,600 kg. This change will promote tourism and the overall RV experience in Ontario, as well as providing new opportunities for manufacturers.
Although the previous requirement was a Class A license for towing over 4600 kg, it wasn't rigorously enforced.
Dave