Your van is going to come from the factory with inherent radiation issues (EMF) that will negatively impact your health.
This video will touch on some that are common to the Ford Transit, and many other popular vans like Mercedes Sprinter, and Dodge Promaster.
Once you build it out with fans, fridges, inverters, batteries and dozens of feet of electrical wiring, you will add to the radiation exposures.
There are good solutions available to mitigate the EMF in your van.
To read a long-form article about vehicles and EMF (electromagnetic radiation), see my blog: www.optimaldwellingspaces.com/post/7-ways-to-protect-yourself-from-emf-in-your-car
For help with your car, van, RV, trailer or other forms of transport, setup a free intro consult with me here: www.optimaldwellingspaces.com/services