Here's the calculations as I see them (
see link):
Gross Combined Weight
20,820
Truck Weight (hitched)
10,780
Truck Weight (truck only)
7,980
Camper Weight
12,840
Pin Weight
2,800
Pin Weight Percentage
21.8 %
Everyone has differing opinions but, I'd want to make sure that you're under on the truck's GVWR, the truck's rear GAWR & combined tire load capacity (vs. your hitched weight of 5940), the truck's front GAWR (vs. your hitched weight of 4840), and finally your GCWR.
On newer trucks, you can find the GVWR and front/rear GAWR on a sticker on the doorjamb.
The tire load capacity is going to be on the side of the tire in really hard to read writing.
And the GCWR is usually in your owner's manual or manufacturer's towing guides.