Me Again wrote:
Gooseneck trailer pictures
Most seem to have the frame all come together at the front.
5th wheel trailes are not built this way.

Many newer fivers are worse than your picture. New notched front cap units do not have a full crossmember across the front of the pin box brackets. Instead, they are notched as well and attach to the outside frame rails just a few inches ahead of where the rear crossmember attaches and therefore flex more under the same forces. What works ok on an older, square front fiver could be more problematic on a newer model.