Dan,
A fully loaded R22, boat, motor and trailer comes in closer to 4,000 lbs,  
depending on how the boat is equipped. Plan on getting something with a 5000  
pound towing capacity. You want to have the vehicle rated to tow more than you  
actually are because you will also have additional weight within the vehicle. 
I  tow with a Dodge 1/2 ton pickup with a V-6. I haven't towed through any 
steep  mountain passes, but around here it's enough for what I use it for.
 
Rummy
Anderson, SC