Well it is esy to figure. Go to your truck and look at the sticker by the drivers door.
What you want is the curb weight and the Gross Vehicle weight rating. Subtract curb from GVWR and that is your payload.
Now add up the weight of all passengers and gear you plan to put in the truck.
Subtract that from payload.
You now know how much hitch weight you can handle. Hitch weight is about 15% of trailer weight and according to PUma is 1128 pounds with rig empty; if you put water, groceries, clothes etc in the rig 15% of that weight will be hitch weight (usually)
If your truck is truly a half ton payload then NO YOU ARE OVER PAYLOAD CAPACITY by 600-800 pounds
Where it states hitch weight insert pin weight
Traveling with my best friend, my wife in a 1990 Southwind