The first step is to figure out the overall design idea that would let me:

- Store the long windsurfing boards and gear with access from the rear doors

- Fit the bicycle, also with easy access from the rear doors.

- Find the place for the kitchen to include fridge, sink and stove.

- Fit the Queen bed with minimum effort to convert to sleeping.

The second step is defining any cut-outs for additional windows or ventilation. The van has windows all around and auxiliary AC, which did not require any updates. In hindsight I would get a van without auxiliary AC and put in ventilation / heating / cooling in the roof myself.

The third step is insulation all around. I removed all the panels and insulated with Styrofoam and insulating “bubble wrap”. According to other articles one should avoid to use PU foam in tight spaces to avoid any condensing  between the sheet metals and subsequent rusting. I avoided it and after 5 years I do not have any rust. I double insulated the sides using both, Styrofoam first coverd by the “bubble wrap”. In tight spaces I used the standard insulating known from house building based on glass fiber.

The fourth step is framing out the van. I used 2x4 that I inserted between the sheet metals in as many spaces as possible. This framing enables easy attachment of furniture later in the build process.

The 5^th step is the installation of the laminate flooring, over floor insulation. It is very important to install duct work for all electric wiring prior to putting the floor down. I ran to ducts from front to rear on either side and 3 ducts from left to right. The flooring is very durable, but the temperature cycles crack the seams open over the years. Not sure how to avoid that, and it still looks very beautiful.