You won't start to lift weight off the front axle until you place weight aft of the rear axle. This is a common problem with pull trailers especially without a weight distributing hitch.
My problem is the five passengers, a load of firewood and gasoline loaded in the front of the bed.
I'd have to say I'm truly maxed out. I wouldn't want to get any heavier on the truck weight.
The fifth wheel is pretty well loaded down too. Six, yeah count
'em six ATV's in the Toybox, tools, compressor, food, etc.
Glad I got my '03. Sure feel and use the extra HP when I'm towing.