I realize this is not the question your raised: But I would not want to carry an Eagle Cap 850 on an SRW when you could choose the stability of a dually.
My 2015 Ram has a sticker payload of 4,300#. This was confirmed by weighing the truck on the way home from the dealership. The Lance 815 I carry weighs about 2,400# wet and loaded for a trip. This means after folks and back seat stuff I have about 1,200# to spare. I would add about 600# to the camper but wouldn't want to add much more than that.
According to TCM, the Eagle Cab 850 has a dry advertised weight of 3,367 which means it's going to weigh at least 4,400# ready for the road. There is no way I'm gong to even begin to attempt to carry that much weight on my truck. It just wouldn't be a pleasant drive much less a safe one.