See that's why this topic is a bit confusing. My understanding is the GVWR (Gross Vehicle Weight Rating) equates to the maximum the truck itself can way including cargo. So my truck's curb weight is 5551 lbs which gives me a payload of 3049lbs. What needs to be considered in payload again anything in the truck the hitch and the tongue weight of the trailer. Outside of that, nothing in regards to towing or pulling.
Thats why i liked that brochure becuase the GCWR is the combined weight of the truck and trailer. So I calcuted the truck capacity including peeps,dogs, stuff, hitch and tongue weight. Then the GVWR of the travel tralier (fully loaded). My understanding is if my calculation are under the 15Klbs, then I should be safe.
Now someone can tell me otherwise.
Your understanding is mostly correct, couple of things to point out though:
Vehicle cannot exceed GVWR. Unless you scale the truck (empty) there's no way to know curb weight, or calculate payload.
Also important is GAWR, which is axle weight rating. When towing, if the trailer isn't loaded evenly (i.e. whatever you're carrying is sitting on the axle(s) not the tongue) it will overload an axle. This is why many semi trucks can move the receiver forward and backwards, to help distribute the weight legally. Same applies when hauling.
GCWR is determined by the class of license plate on your truck and trailer. If you're scaled and you're over what you're plated to weigh, it'll cost you.
Calculating without actually weighing is useless. You're just guessing.
It's highly unlikely you'll get scaled if you're not running commercially, but it does happen occasionally, and they couldn't care less what your excuse is. If you're over on axle, gross, or plates you're getting a ticket.