This is unbelievably well thought out and put together. Inspiring stuff. Thanks for sharing.
Since this is an off road trailer, are there any concerns with the box being built directly onto the chassis, rather than built separately and then attached to the chassis with a mounting system? Truck campers seem to use mounting system - do they experience more flex in the chassis? Perhaps a stiff frame design and suspension means its not necessary?
I've seen some builds here that simply use heavy objects to weigh down the sandwich layers of a DIY composite FRP wall. How critical do you think the vacuum table is?