My towing guide book shows the max tow rating for the 1500 series van at 6,200#. It will do it but like mentioned before if you have a FEL or implements you wil get real heavy real quick.
Also remember that tow ratings are assumed. What they do is take the weight of the truck and subtract that from the GCWR. Lets say for argument sake your GCWR is 13,000# and the van weighs 6,500#. The manufacture has to give a credit for a driver and fuel when getting the tow ratings certified so let say in this case they give 150# for the driver and 150# for the fuel. That puts your van at 6,800# rolling down the road with you in it and when you subtract that from the 13,000# GVWR you get the 6,200# tow rating.
The issue I see here is you said you work out of it. How much do you think you have in the back in tools, ect? Lets say 1,500#. That now comes directly off your tow rating so that 6,200# magic number is now 4,700#.
Remember, at the end of the day what matters is that you do not exceed the max GVWR or GCWR for your vehicle and do all this while not exceeding any axle or tire rating.
The GVWR for any vehicle can be found inside the drivers door on the data sticker. You will usually have a rating for the front axle, rear axle, and the GVWR. The sum of the front and rear axles is usually more than the GVWR but at the end of the day you must be under the GVWR and do not exceed the axle or tire ratings.
Hope this helps.
GVWR = gross vehicle rating = max weight of the vehicle, includes cargo-fuel-passengers, and trailer tongue load.
GCWR = gross combined wheel rating = max of the vehicle as described in GVWR and the weight of the trailer and its contents.
Simply way to see where you are at is have things weighed.
Chris