Thank you for good words. My plan is to have modularized design with possible transformation from the passenger to RV and back. All floor mounted modules are going to be mounted to the factory seat mounts or within each other. Upper overhead cabinets will be mounted pretty much permanently with FIBERGLASS bar insulation between 80/20 Al frame and chassis.
A very easy removal of the module #3 will allow me to reinstall the factory middle seat give me the 8 passengers van. The Webasto Dual Top water heater and furnace
combo, 2 AGM 6V batteries, fresh water and gray water tanks are going to be mounted below the floor.