Double check your numbers but if the unloaded weight is 6800 and cargo capaicty is 1400, that means you are looking at a fully loaded weight of 8200 which exceeds your 7900 tow rating.
Pin weight probably is OK assuming you don't load up a few hundred lbs of fire wood or other stuff in the truck bed.
If you are careful with keeping the truck and trailer lightly loaded, you can probably stay under weight but if you didn't already have the truck, I would tell you to move up to a 3/4 ton and you may find it's still a nice upgrade when you consider the bigger brakes and stiffer suspension.
Should work but you are flirting with the limits.