Hey JP,
I have a buddy with a prowler's and a triple axle trailer also (the guys there should know him, he has the Buick v8 car). He already has alot of wear on the rear tires from loading his car, and he backs it in.
If you haven't noticed any extra wear now, maybe no big deal. His rear axle wear is significant. Of course, his is a Warrior 5er, so take it fwiw...
If it works, it would sure be easier than the alternatives...