Please don't confuse the Andersen Ultimate hitch system with a gooseneck hitch - it is not a gooseneck adapter. It merely anchors to the truck with your existing gooseneck ball. True gooseneck adapters have a vertical "pole" that attaches to the pinbox on the trailer. Gooseneck adapters usually void your frame warranty on the RV and put stresses on the trailer that can severely damage the pin box and trailer frame.
The Andersen system is an excellent choice. We towed our first 10,000 miles full-timing with one and loved it. The only reason it didn't make the transition to our new (to us) F350 is that our RV dealer couldn't get the "picture frame" adapter for the Ford puck system in time. We had to bite the bullet and buy a new hitch to fit the OEM Ford system. PullRite now has a similar system ("UltraLite" maybe) that is the same concept. Either hitch would be a good solution for you.
Rob
U.S. Army retired
2020 Solitude 310GK-R
MORryde IS, disc brakes, solar, DP windows
(Previously in a Reflection 337RLS)
2012 F350 CC DRW Lariat 6.7
Full-time since 8/2015