I have an the Anderson Ultimate II gooseneck to fifth wheel conversion kit, possibly the style you have seen. Hooking up is simple, you just look over your shoulder and line the ball under the adapter then raise the landing gear and push the cable pin in and twist to lock. It tows super smooth, can be removed or installed into the truck in less than a minute, weighs 30lbs. Allows me to make full use of my bed when needed, and easy.
My truck is a 17 Ram DRW, 4x4, Mega Cab. Using the trail Air Tri-Glide, I can get almost to 90 degree turn before it would hit cab.
My 5er is a 44' Voltage 3818 Toy Hauler, about 20K lbs fully loaded.
2014 Voltage 3818 (Epic I & II)
2005 Fleetwood 31ASV BP Toy Hauler
2017 Ram 3500 Longhorn DRW, 4x4, 3.73, Aisin
4 Seat Long Travel Sand Rail, 97 Jeep TJ Rock Crawler, 68 Roadrunner, Various Quads