Go look in your driver’s side door jamb there should be a sticker that indicates “max load of passengers and cargo”. That number will be your limiting factor for a fithwheel. A fithwheel will place roughly 20% of the trailer weight on the truck. That “pin weight” is deducted from the number I mentioned above in addition to any other equipment/cargo or passengers traveling in your truck. By example a 12,000 lb fifthwheel will place roughly 2400lbs of weight on the bed of your truck. If your truck sticker reads something like 2900lbs that only leaves you 500lbs for yourself, your hitch, and anything else going in the truck. Once you report back with the number on the door jamb and roughly how much weight you expect to carry in the truck we can work backwards to find the maximum trailer weight. Hope that makes sense!