Just because I enjoy the process, we stopped and got weighed. This is likely to be as close to as heavy as we'll run. I didn't have a full tank of fuel, unfortunately. I would guess we were down by 1/3 of a tank (so, maybe 80-90 pounds less than if I were full (figuring about 11.5 gallons and 7.5 pounds per gallon).
We were leaving our house for 2 weeks of camping and 1 week at a beach house and then a weekend of camping before heading home. We also had my mother-in-law riding with us.
The truck bed was as full as I could get it:
The first weighing (truck and camper):
The second weighing (truck only):
Playing with the numbers, I get:
Loaded truck weight: 5300 + 6660 + 85 = 12,045
Pin weight: (5300 + 6660) - 9420 = 2,540
Camper weight: 2,540 + 12,280 = 14,820
Pin %: 2,540 / 14,820 = 17%
Truck's GVWR is 12,300. The camper has two 7k axles and tires to carry up to 13,680 on them (at maximum inflation).
The camper itself had freshly full propane, my usual amount of freshwater on board (1/3-1/2 of a tank), a full water heater and the plethora that I typically carry (2 cases of bottled water and 7.5 gallons in jugs). We also carried our few soda-pops but no beer (though, I typically carry 1-2 six packs at most). We did do grocery shopping before the trip and had a full inside fridge. Wife had more clothes than usual and otherwise, everyone else had what is normal for them.
(Edited to tweak formatting and spaces.)