This is all wonderful info, thank you! A few follow-ups:
- The tongue weight of 800lbs seems over the factory recommended 700lbs, were you able to weigh your whole set up? Maybe a broader question, where does one go to get their total GCWR?
- How accurate is the TPMS to manually checking the tires? The manual recommends 39psi for the rear tires when towing and 33psi for the front, did you inflate all 4 tires or just the rear?
- 80 gallons of water is 667lbs, wow! At an RV park, do they have fresh water hookups on each site or do you fill-up at a central location prior to parking? Great tip to avoid weight especially if water is available at the camp site.
1) From the manual for the 2020 LX570. These numbers have changed over the years, with significant changes when SAE J2807 was applied. I wouldn't sweat +/- 100lbs, and a properly adjusted WD hitch will distribute weight to the forward axle, and back to the trailers axle.
2) Don't worry too much about precision or accuracy with tire air pressures. They change and fluctuate anyways with atmospheric conditions, and there's margin, so it's futile to geek out here. If towing at the upper ends of the spectrum, it's reasonable and can be beneficial to go above those pressures by 3-5 PSI, particularly in the rear axle.
3) I always travel with full fresh water tanks, though full tanks in my Airstream is 40 gallons. My laden trailer is almost 8k and 1200lb tongue. I tend to boondock or camp without hookups, and an RV doesn't make a great home without water. Water is usually the constraining resource.