What materials to use for the floor? I explored all of my options, debating between using laminate, engineered wood flooring, and sheet vinyl. They each had their benefits. Laminate and sheet vinyl were the cheapest and lightest options; but flexible so the sub-floor would have to be dead level or it could feel squishy in places or bubble up. Engineered wood flooring is expensive and heavy but provides a solid foundation for the rest of the van.
First let'd talk about the sub floor though. This will be the foundation for the van so it is important to spend some time with this. There are grooves on the metal floor of the van which can make this difficult. I did my best to fill all the voids underneath with strips of reflectix before putting down some plywood. For the plywood sub floor I ended up ordering a kit from an up-fitter (the black layer seen underneath the wood flooring) because I couldn't wrap my head around how to secure it to the floor without using a bunch of adhesive. The kit uses bolts to secure the sub floor to the bottom of the van. After receiving it I could have easily done it myself, but never would have thought to use the bolt holes that are built into the frame. Using an adhesive is a good option too, I just didn't feel like dealing with it at the time.
The flooring I went with is a whitened oak 1/2" thick engineered hardwood flooring. I would have preferred it to be 3/8", but I could not find anything this thickness I liked that was in my price range. This flooring will be super durable and has a matte finish, so it shouldn't be super slick like the shiny floor we had in the Econoline.
I have installed flooring a couple times now, so I knew what to expect. I made things a bit difficult though by trying to save some money (wood floor isn't cheap) and choosing to use 1/2" plywood in places I knew would be covered up anyways (under cabinets, the bed, etc...).
After paneling the main wall of the van I knew I wasn't going to have enough supplies to use it for the ceiling as planned. I decided I would use the flooring on the ceiling too. This is a look I had seen done before and like it quite a bit; I wasn't sure how it would translate to such a small space though.