Since the micro-mansion's original framework was that of a shed, there was no subfloor created to install the insulation in. Even though the downstairs living area is only 6'6" I've decided to built a subfloor from the inside and up.
I will lay the 2"x4" framework on top of the existing plywood floor then fill the newly made cavities with insulation prior to topping it off with a new subfloor. I will lose 4" in height but since we are all under 6' at this time it shouldn't be that much of a loss.
Another option was to place the insulation on the underside to the micro-mansion, however it was important to keep the floor joists accessible for when the micro-mansion is placed on a trailer, which is the long-term plan.