Help with wheels and tires.

You cannot do estimates by using total tire capacity because you will be carrying the majority of the weight on the rear. You need to look at what weight will be on what axle. So you will have a 7960 lb tire capacity using Nittos on the rear axle with 7000-7500 lbs typical weight. When towing, you will want to do the trip with empty tanks and fill when you are close by where you little distance to travel and hopefully lower speeds. If you are not willing to play it that close, you need to look at 245/70R19.5's and figure out your clearances. I know the Vision rims have less inside offset than OEM or Rickson, so this may be an advantage for you on the front.