Flooring Plans

 Here are my plans for the floor.  Not sure if all that blocking will be necessary over such a short span.  I'll decide based on how straight the lumber is.

And here is my plan for the insulation and sheathing.  The whole exterior will be wrapped in 2" of EPS rigid insulation.  Under the floor I will attach a thin layer (3/8") of pressure treated plywood to keep out the critters.

The walls will be sheathed in plywood, covered in Tyvek, then 2" of rigid... following by strapping and finally the siding.

There are pros and cons to putting the Tyvek outside of the rigid, and also of putting the rigid before the plywood.  But in the end, it will all work as a system, and will breathe well since I've chosen EPS over XPS foam.