Major Sway Problems! Any ideas!?

Selling current RK model for an FK model travel trailer may also help in this situation. If you have 5 people in your truck, you already have lost potentially 1/2 of your payload. Yes, I would agree that you are probably closer to 2300-2600 lbs of actual payload. My family of 6 was closer to 1200 when my kids were adult sized teens. I pulled a 24' FK trailer all around the US and mostly NW US, in winter with snow and ice on the road to ski areas, upwards of 50-60 mph cross winds across bridges over the columbia river. NO SWAY. Then again, a noted, I had 13-15% HW. This is with no WD, wd and later a dual cam. Yes I did notice some difference with no bars, vs WD vs a dual cam. Dual cam being the best setup. BUT< I still would have no qualms about towing barless!

Your trailer has some issues that need to get solved first. not so sure a 5w is absolute best option.

Marty