Yes, Highlander max tongue weight is 350 lbs. i guess we took it for granted with the tent trailer and never had issues with sagging to think about this before.
We are Happy to report that this weekend trip went wonderful. The pull was smooth and I did not feel like I was towing most of the time. Minimum drop ( about 1 to 2 inches loaded both TV and trailer. This is similar to when we have two adults in the back seat). Cooler over the axle in TV and some light clothigs.
This is after taking out the two propanes and put one over the axle ( bought cap for the propane connection at the front of the Trailer to lessen the load and prevent road debris from entering the gas line). Placed three 25 lbs water jugs in the back storage, solar panel on the rear bed, beddings and such under the front bed, food, pots and pans, shore cable etc, under rear bed, front storage only has light items such as chairs, towing choks, mat, tarps, kids' light toys. Tongue weight is about 340-370 lb using bathroom scale method to meet 350 lb tongue weight. Total cargo for the trailer is 650 lb. dry weight 2100 + 650 lb remain below GVWR of the trailer. TV remains within 2003 Highlander front and rear weight rating.
We basically reduced the front load, rearranged the load (since I weighed all items just to deal with this). After unhitched, TV did not bounce which meant our suspension is still in good condition as the mechanics confirmed.
Thank you all so much for the forum's suggestions and ideas. We will still keep a close eye out for the load and weighing method next time. If we did not have the issues, we would not have learned a lot more about trailer.
Newbies to Aframe 2015
2015 Rockwood A122S
2003 Toyota Highlander, V6