I second the CAT scale approach.
You weigh the TV and re-weigh the TV and TT combination. It also gives you before and after axle loads.
This is also the true weight not the average weight often found in the brochures.
Locally it cost $12.00 if the two weightings are done in 24 hours.
Twenty six foot 2010 Dutchmen Lite pulled with a 2011 EcoBoost F-150 4x4.
Just right for Grandpa, Grandma and the dog.