DOT, from what I understand, only cares about RAWR and tire rating. The tax man might care about GVWR because you didn’t pay enough tax for your loading. You’ll also read about how if you are over GVWR that your insurance won’t cover you in an accident and all that jazz. This is another internet lore and I’ve not seen a real example where his has happened (it may exist and hopefully someone with a link to a case will post it here). Last I checked, it’s illegal to speed, make an improper left turn, drink and drive, but coverage isn’t automatically denied. I suppose if you were way over loaded, to the point of gross negligence, you might be in trouble. Also, if you are at fault, you are at fault; doesn’t matter if you are over weight unless you were so overweight that it was a contributing factor in the accident then maybe there’s additional punishment or liability? And anyone can sue anyone, but contingency fee lawyers much rather go after insurance policies because they actually pay. Good luck getting a $500k+ judgement paid by Joe Schmo; garnish his $50k a year salary and renew the judgement every 7 years. That’s how those big accident attorneys get rich. (Insert rolling eyes emoji to indicate sarcasm; lots of folks can’t detect sarcasm just by reading text).
if you’re going fifth wheel, the 3500 setup is preferable. They are harder to find. The 2500’s are plenty capable. Just go to a campground and see what gets towed with a 2500 class truck of any brand.