That's some load Brian, but credit for doing the hard work and assessing your pack properly.
One thing not mentioned is whether or not you have Quadralift... just regarding my "seat of the pants" commentary in which I have found my MY14 (with QL) quite underdampened with only 260Kg on the ball, and just a 55L fridge in the boot. How did yours feel heading to the weighbridge? Was it porpoising?
I expect you are aware that Jeep "recommend" a WDH with loads over ~2200Kg. Just saying... not bashing you over the head with it. I try to avoid using one too
I am working off this being your van with all standard features listed: Patriot SE-L - Sunland Caravans
My thoughts are:
- Move second car spare wheel to under van, preferably over axles, otherwise as near as water storage permits. To hang it, get a "spare wheel winch" from the wreckers or eBay.
- Remove second battery from car and move to storage in van, preferably over axles. Rewire to use van power when connected and install second battery to car when not. Or better still delete the second car battery and borrow a Lithium out of the van when required.
- Move any particularly heavy relocatable items in drawbar box or in forward storage areas to over axles. Avoid shifting weight to the rear bar due to the effect on stability.
- Cull some stuff.
- Consider repowering car with Lithium batteries.
- Use WDH and remove when required.