On top of the insulation we laid down OSB flooring. We used the old carpet as a template, cut it from 2, 4x8 sheets. In hindsight we should have cut them width ways, we used a full sheet on one side and then cut a much narrower slither, roughly 12 inches wide to run down the driver side. As I say, I'm not happy with how it turned out due to the seat base cutouts for the rear seat being too close to the seam and therefore weak. If we ever re-do the floor, I'll change this.
On the roof we also installed the Pink Panther insulation. We measured the space between the roof supports and cut the sheets slightly larger so we could trim, and get it to fit nice and tight to prevent squeaking, we did this early summer and as of now, January there's been no squeaks.
We continued this on the sides and tried to cover as many of the holes as possible on the inner metal to prevent the high humidity air entering the internal airspace between the metal layers, ( you'll see what I mean once you remove your panels ).
On the walls it was too hard to install the foam board so we cut smaller areas of Reflectix to fit the varying shapes along the walls and wheel wells. We're currently still in this state as I'm not entirely sure how to move forward with the walls.
We'll also be insulating the passenger area floor and doors along with the rear doors when we can find somewhere to work on the van, we've moved to Portland and we're in an apartment again which means we've nowhere to work on our van.