I have run a GN adapter since the late '90s, on all the 5'ers we owned the only trailer frame that broke was from a 5th wheel hitch, which is why I went with a adapter. At the time I didn't know that they made them and made my own. the biggest 5'er I've had was a 3400rl montana over 16,000# loaded. I travel for work so on to go alot and a lot of miles. One of the guys that I work with has a cougar and noticed his front cargo door was getting tight he found that the frame was twisting, after calling the mfg he also found that for about 1 1/2 years this was a design defect he runs the 5th wheel hitch. Anyways I pulled the skin down on mine to check it out same mfg and no problems or concerns. I'm a millwright by trade 35 years and know what to look for. IMHO I would not run a 5th wheel, when you run out of movement on the hitch you start twisting the frame as per my 1'st trailer and when I want or need to move down to road I have the HP and torque to do it. I'm also on diesel forums and we get into some dicussions about FW verses GN and it is hard for me to believe when they say they have seen lots of broken frames when in the parks and I see a GN adapter I usually go and ask them if they like it and had seen bent or broken frames, not one as of yet using the adapter.