This shows some numbers for a Gen3 Tundra with an overlanding build and a small pop up camper.
Oem curb weight= 5,800 lbs,
GVWR = 7,300 lbs (1500 lb payload)
Loaded weight = 8,600 lbs... so 2,800 lbs actually added to the stock truck.
And 12.1 mpg on the trip too, vs 15.6 mpg for the guy...