Hi, Need help to properly insulate and fix my existing insulated sunroom. 

When i bought my house 3 years back, realised that the air was smelling little like mold in the sunroom( 144 sq ft ) 

I showed to couple of contractors they did not give me any convincing solution and pricing because they did not know what was going in out there.. the way the sunroom was constructed on a wooden deck and brick locking veneer stone porch skirt.

So i decided to rip open the porch crawl space.
1. Removed linoleum found the subfloor was rotten on one corner, because the water was comming in through one of the flashing.(remove subfloor)
2. Removed the fiber insulation which had lot of mold.
3. Found the fiberglass insulation has mice and the crawl space had opossum living in.
4. The sunroom was on gradient, on one side the rim joist was half burried into the soil. And the rim joist wood was rotting.(replaced the supporting rim joists)
3. Due to gradiant on one end the posts were under the soil along with the rim joist with the cement and wood both under the dirt..(dug soil leveled soil, poured cement, now the cement base of posts are 6 inches above the cement slab).

Now that am at this point. I am really apprehensive how to re-insulate the crawl space.

I was planning to do the following:
1. Put foam board on the rim joist from inside and seal the edges with spray foam.
2. Below the rim joist and the whole sun room cover it with wood ply board, put vapour barrier or a 20 mil sheet on the ply from inside the sunroom.. 
3. Put rockwool for insulation on the vapour barier/ plywood.
4. And finally put the floorboard..

Then to cover the sunroom skirt, use cement sheet all the way down to the concrete slab and put back the veneer stone as the sidings.

I hope i was able to provide you all with the proper details required to guide me to fix this diy project.