Pin weight is important but it's only part of the entire payload calculation you need to do.
Find out what your truck weighs with a full tank of fuel. OBTW, gas weighs 6 lbs a gallon.
Then calculate how much your cargo, passengers, gear & pin weight is. Pin weight is usually 15-20% of the trailer's weight.
Add that all together. That is your Gross Vehicle Weight (GVW).
Now go look up your Gross Vehicle Weight Rating (GVWR) which is the max your truck can weigh.
Then...
Get some weights for the trailer. I'd recommend the trailer's GVWR. You can usually get dry weight (empty) and the GVWR for the trailers either from the manufacturer's website or off a sticker on the trailer. The difference between the two is how much stuff you can put in the trailer. Don't forget that you will be adding fresh water to the trailer. Most folks don't do that until they are close to their destination and they dump before they come home. Since water weight 8.4 lbs a gallon that can be a significant number depending on your fresh, black and gray water tank capacities.
Ok..now that you have determined your truck's GVW & your trailer's GVWR, add them together. This gives you the Gross Combined Vehicle Weight (GCVW). Now, go look up your truck's Gross Combined Vehicle Weight Rating (GCVWR).
If the GCVW is more than the GCVWR, then you have exceeded the truck's weight rating which is not recommended.
There are some good calculators online that you can plug numbers into for a quick calculation.