Well you either go by the 10,000 lbs. or not, up to you. If not make sure your axles, wheels and tires are rated for what you want to carry.
I have the same 10,000lbs GVWR and have a commercial canopy that puts me at 10,800 lbs., I ran that way for almost two years and my truck did not self destruct. I am planning on a truck camper so decided to upgrade to 19.5 wheels and tires so I don't have to worry about them being overloaded.
I have the same rear axle as a one ton truck just a lighter spring pack, the axle is rated for over 10,000 lbs. The truck might not handle like you want and you might have to do some mods to the suspension. A one ton would handle what you want to tow so compare your truck to a one ton and see what the differences are and go from there. I am comfortable with doing this, some people are not.