Your current half ton Suburban 'can do it', but not for long and not a good
situation when the need to manhandle the whole setup during whatever emergency
situation you might encounter...
The wheels won't instantly fall off, but they will sooner than if
withing the 'true' ratings
Do your own risk management decision, or if you are just looking for the 'sure you can'
types of advice...you have and will get tons of that...but there is no skin in the
game here on these freebie forums...you can have a thousand different
copies of those "sure you can"..."I've been doing it for decades" and
they will NOT get the ticket...the driver will and/or is responsible
for the setup
How long is dependent on lots of things. Terrain, ambient's, how you drive, condition
of your Sub, etc