I hooked a 2" ball to my 3/4" mounting hole on my Rancher the other day and towed around a 350lb trailer with another 200lb load up and down some pretty good hills and muddy slopes. It preformed wonderfully. The only problem would be that the ball is located a little too far inward of the ATV to make sharp turns without the trailer hitting the rear tires.
I think I could have easily added 400lbs more to the load without a problem.

gary