Do a quick Google search for CAT certified scales locations. They are at almost every truck stop in the U.S. You need to do a three weigh process.
1. Weigh the truck and trailer together. There are three scale pads and your truck front tires go on the first on. Truck rear tires go on the second one. Trailer tires go on the third one. Use your weight distribution hitch like you would normally.
2. Do not move the truck after your first weight....simply disconnect the spring bars from your WDH so that all of the tongue weight is on the hitch ball and not being distributed.....get another weight.
3. Hitch the spring bars back up and pull off of the scale. Find a place to park out of the way and unhitch from the trailer completely. Pull just the truck back onto the scales (pad 1 and pad 2) and get another weight.
Hook back up and go inside and pay for your three scale tickets. Pricing should be about $11 for your first ticket and $2 each for the other two...= $15 total.
Drive home and get on the computer and look for this website.....
RV Safety|RV Towing Calculator|Tow Ratings|GCWR. Click the link at the top of the page called "4 Step Weight Safety Plan" and make sure you use the one for tow behind trailers and not the one for fifth wheel trailers. Follow the instructions and soon you will know more about your trailer weight than you want to know. By the way, you can use the calculator without having to know all of the information in the worksheet. Hope this helps