We used an Andersen Ultimate (steel, rail mount) in our GMC Sierra short bed. It was a good hitch and only moved about 100 lbs. off the front wheels. The aluminum versions are ball mount. PullRite now has their version called the SuperLite which is also a good hitch. From an engineering point of view, I'm not a fan of the GooseBox because of the torsional forces that type of adapter puts on the front of a fifth wheel RV. Fifth wheel frames are not designed and made like gooseneck untility and stock trailers.
Rob