NEW!
The province of Ontario announced a new rule effecting RVer's, Effective June 16, 2008.
Look at Publications here http://www.mto.gov.on.ca/english/pubs/rv/index.shtml
Also look at page 2 at: http://www.mto.gov.on.ca/english/pubs/rv/part2a.shtml
Your Pickup, if it has Commercial Plates [Black letters with white] may need to have your licence upgraded
See link: http://www.mto.gov.on.ca/english/trucks/regulations/trailers.htm
Re cap
"Any tractor-trailer [ That includes an 5th Wheel or Travel Trailer ] or combination of motor vehicle and towed vehicles where the towed vehicles [Trailer 5th wheel ] exceeds a total gross weight of 4,600 kilograms" or 10,141 pounds