When I bought my 38FT Silverback Fifth Wheel, I got the Kingpin changed to a Reese Goosebox and I had a B&W Turnover Ball hitch (
https://www.hitchweb.com/category/hd...ball-gooseneck) installed in in the bed of my new 2015 2500HD Silverado. The only thing I changed was the standard turnover ball to a 3" offset ball to clear the cab of the truck when making sharp turns.
I had this set up for 4 years and travelled through the Rockies and Newfoundland and never had an issue. The other thing I love about this set up is, when I don't pull, I just flip the original turnover ball and I have a flat bed in my truck.