Tried doing this in Photoshop CS6... It ended up not going well

The Mountain Difference Cloud layer is near impossible to make
The Masking options are different and as a result the masking portions don't work... which is a lot of it. I got to trying to sculp mountains and I couldn't get it to look well.
I'm pretty sure the Land type layers would work, but from what I have seen GIMP's airbrush is better or something about Photoshop is making it hard to get it right.