OP wrote:
If my trailer dry weight is 5,500 lbs and we add 1,500 pounds of supplies travel (including propane) with drained tanks save of bit of fresh water then my tongue weight should come in around 700 lbs which is below the 15 lbs over the above. Add to this that properly equipped the Tundra is rated at towing up to 10,100 lbs and I'm at 7,0000 lbs / 69 of the total towing capacity and I'm at 87 of the GCWR of 16,000 lbs the then what am I missing ?
Your trucks towing capacity is basically meaningless. Sure, it probably could pull the 10,000 pound weighted flat trailer used to determine this number.
What your missing is that payload will be exceeded before you reach your towing capacity. A lot of payload is taken up by tongue weight. Even the weight of the WDH setup you plan on getting subtracts from payload.
So you estimate 5500 lbs + 1500 lbs of gear + some fresh water. Lets say your hauling 10 gallons. At 8.34 lbs per gallon, that's 83.4 lbs. So just calculating tongue weight given these weights is (5500 lbs + 1500 + 83.4) X .13 = 920 lbs.
Check your manual or door jamb sticker for the statement weight of occupants and cargo should not exceed xxxx lbs. What is that number?
Subtract 920 lbs from it. Now, subtract the weight f your camper shell, then approx 100 lbs for the WDH setup, then weight of passengers, pets and cargo.
The high front wall of the camper is a sail. Much different towing experience.
I'm not dissing on your Tundra - they are great tow vehicles. In your case, I'd take the advice to load it up and weigh it. Otherwise, go with it and let the chips fall where they may.
Again - good luck.