Thank you for all the suggestions. This exactly the feed back I was looking for.
Also, I need to figure out how to make the fake stones shader look more natural. I think they need to have color variation and well, look like rocks. I will work on the haze as well. BTilson, yes there is noise is the shadow parts. I will correct this when I do the final render. Thank you.
Thanks again. I will use all your suggestion in the next version.
Marc