Another Jeep Cherokee (XJ) data point.
Curb weight: 3350 lb
GVWR: 4550
Payload: 1150
My "vanilla" build used the following heavier than stock parts:
TNT Long Arms
TNT Stiffeners
JKS Sliders
Dana 30 front axle converted to WJ brakes, high steer, WARN hub kit, ARB locker
IH Scout Dana 44 axle w/ WARN full float kit, ARB locker, Suzuki J1 vented disks
HAD CV rear shaft
ARB Bumper w/ WARN M8000
16x8 steel wheels, 265/75-16 Duratracs
With 2/5ths a tank of fuel and no passengers or gear it tips the scale at 4250 lbs.
Amazingly it still drives pretty decently with the stock tractor engine it came with combined with 4.56 gears in the axles. I'm not really wanting for power at highway speeds or when towing the camper (~3000 lbs). Steep ascents and real altitude would likely make me think otherwise.
By the letter of the specs I only have 300lbs of cargo capacity left assuming the upgrades don't increase GVWR. With all the weight added the Jeep drives much "larger" than it used to; I have no worries with the family on board, loaded and hauling the trailer. Between the extra weight and the large brakes the Jeep handles the load fine. I have an unmodified XJ still and with just me in the Jeep while towing the trailer (unloaded) it feels "scary".
The built Jeep gets ~17 mpg unloaded on the highway (~110 km/h), with the trailer in tow it'll do 18-19 mpg. The top of the trailer is level with the roof of the Jeep so I'm guessing it cleans up the aero somehow.
I don't recommend this setup but I'll use what I have till it's used up.