This is a beautiful van build although a little spendy. A huge expense on this build was the pop top, but still nice. Pay attention how David designed his build for several functions.
Going with a passenger van as your base build has its advantages in the fact that the interior work as far as insulation, paneling, heating and cooling ducts, and lights are already factory installed. You will have to remove the benches to give you room to finish your build.
You can find these vehicles being sold by not only private parties but also schools, churches and other organizations. Generally organizations have a maintenance schedule for their car pools so even if there is high mileage the van could still be in very good shape. These can be a very affordable entry price if you are on a budget.