You've done some good work there, tucsonpd, especially in your choice of 10 ply tires for the truck. I'm guessing they're E-rated. The problem is, your suspension is still at the 1/2 ton level. Take your truck down to the CAT scale at the truck stop on I-10 south of Tucson and weigh it. You could also get the weight if you drove it to the landfill. Either one is quite accurate. As I recall, the CAT scale costs $15 and the people in the truck stop were very accommodating. It's possible the landfill is cheaper.
The CAT scale is better though, because you can weigh each axle on its own scale, and, if you take your trailer, you can get the weight of it, and your two truck axles too, so you'll know exactly what load is on every part of your combined rig. I'd be willing to bet a serious night of drinking at a bar that your trailer will weigh more than 4365#. You can shave off 300# by towing with empty fresh water tanks, but you'll want full propane tanks. And, I bet your trailer has an air conditioner and some other optional equipment, like cabinets, maybe a microwave or oven, etc.
I'm not trying to be a wet blanket, but my truck's GVWR is 7200# and its normal running weight with just me inside is 6520#. Things like 4WD, the tow package, and other optional factory stuff (which is NOT included in the "basic weight rating") severely impact the actual "delivered weight" of a vehicle.
- Jack