I have a 2006 Montana Mountaineer that has GVWR of 12275lbs but has 6lug 5200lb axles. This doesn't seem right to me but I guess they deduct some for pin weight. It came with Load E tires but I've had...
Weigh it hooked up for accurate amount on tires/wheels. Even if unhooked, a large percent is on landing gear. You likely won't have more than 10K on the two axles.
What size tires/wheels are you running? Even 15" E-rated should be around 2,830 load.