Good thread good posters. Some quick background on where I'm coming from. I've been commercially transporting Airstreams, Box TTs & THs daily from the Mfgs to dealerships nationwide with my 14 Ram 1500 3.92 ED for the last 3 1/2 years. 372,000 miles all over the US often starting in Ohio to over the mountains to all over the west coast. I've transported lots of 30s some 33s & a 35' floor plan with this truck. Plus some boats & enclosed car trailers. There is pics of my truck on this site towing a 33' Airstream at 8,700 a 33' Forest River Wildcat Maxx with 3 slides at 9,086 and a 35' at 10k pounds "wet" no water. (The rest are dry with only me in the truck.)
Towing an 8k plus tall boxy TH with stability & safety and the family really doesn't compute for a limited experience person and your truck. At least not without an experienced person doing the setup and making the adjustments according to scale results.
Forget any mfg maximum for a second. Safety & stability is mostly in steer & drive axles weights, TW percentage, and speed of travel. 65 mph & less. Soak that in for a minute. Practical use of my last post went past some posters.
That's steer axle between 3,200 & 3,900 and drive axle the same. Example 3300/3700.
Plus actual calculated TW after spreading weight across the three scales.
Not anything else. You don't separate the weight of the hitch itself because it's about dynamic weight not the static weight of the wdh itself, or care about Mfgs dry TW IF useing a WDH and going to the scales.
If the two axles are within spec and TW percentage is in between 10 & 15 percent. (10 is hard to get to) As well as Max Tow your CVW will also likely be within spec. Regardless you will have the actual numbers to check.
As will your receiver. BTW the 4th gen 1500 has a class 4 receiver with according to Ram body builder site a rated max TW of 1,290 pounds when using a WDH. Again that is dynamic weight spread across the three axle weight numbers but seen or calculated by adding the loaded truck axle weights then subtracting the dry truck weight.
Not for legality but for safety & stability based on lots of actual drive and scale time with various trailers & loads. I'd rather have between 6,900 and 7,800 pounds on the truck axles as long as it's fairly equally distributed. At least when you have a long tall heavy flat sided TT/TH that is 8k plus. Meaning if the truck is 6k & the TH is 8k with 12.5 percent TW the joined rig becomes 7K each. Not that you have to keep the truck equal to keep the tail from wagging the dog but it does not hurt.
TH wet weights vary more depending on toys but family of 4 camping will usually need 1,000 pounds over dry weight. So figure 1k plus toys their fuel etc. This should once you have digested it help clear up the eye on the ball thing. And answer the question what can it tow safely. Which is when near the limits, only the scales results as to what you can get inside of the specs can tell you.
Lastly picking the appropriately sized WDH is important in order to achieve proper distribution. I assume you have a factory trailer brake controller. Tires & bags already covered.