83 Lux with a 5.0.... we need a rides section I think
Should be fine with loads of weight provided you can still get traction, I've really only got 1 experience to go off - on sand towing a water cart with a 2H powered cruiser.....it just wasn't going to happen, kept bogging down the second we lost momentum, but the sand was pretty soft and total weight in the trailer + tray would have been up around 1tonne+
But at the end of the day people have towed more with less so I reckon it comes down to the conditions of the tracks on the day. Like I was on a dirt road in the Wattagans after rain once, it was the main road through it so usually suitable for road cars, yet I had trouble getting up a slight incline in 2wd, tires just couldn't get traction. Would have had no chance with a trailer of any weight.
Keep it light, pack everything you need and nothing you don't. If it was me, I'd aim for around 500-800kgs, but I've no idea of what a camper trailer weighs dry, so 500kg might be a bit ambitious.