Take the trailer to a heavy duty truck-trailer shop and have it done right. Show them the
X-Factor crossmember product. Providing lateral support with the purchased product or simply adding steel will help greatly. You can play around with RV dealers, frame manufacturers or the RV builder, but it will only be fixed right when you make it happen. Yes, I was thru this but gave up when Lippert showed me a scrap of paper with an incredibly poor sketch of the proposed repair. I made crossmembers and did 100% of the work myself.
