What is under the deck? Is it wood or concrete?

I would imagine it's wood. I have not moved in yet. I will be there in the next couple of weeks. Since it's a mobile home the deck would have to be removable.

Not sure - what makes me think it might be concrete is the block work around the entire thing. It would actually be easier to have poured concrete in that area than trying to frame out wood... It could go either way.

The bricks are in the front, back and along the sides. It's kind of curved as though something warped a bit. The bricks also go around the house itself. The manufacturer was top of the line when this was purchased and they did a lot of nice things.