Vehicle camper conversion

Basically the job is to convert a Toyota Land Cruiser 70 troop carrier into camper with kitchen, inside shower and toilet, fridge, water tank, storage space , plumbing and electricity, sleeping bed, fridge ( we will be working and designing the interior and exterior solutions to achieve ergonomic and well designed overlanding vehicle). I do have a design and i do have background on overlanding conversions so it will not start from scratch. Finally another important aspect of creating a well designed product is choosing the right material that will be used in the build which should be a very rigid, light and weather resistant material ( ex. Light aluminum composite)