Being one who craves information I am an avid reader of RV magazines. Two of my favorites are Trailer Life and RV lifestyle (Canada Based).
While looking for subscription information for RV lifestyle I came upon their very informative web site.
Click on the link below and view the red column,
"Hitch Hints" Looking for a tow vehicle.
The article is written by a Canadian Airstream dealer and discuses tow vehicle criteria. Enjoy!