OS X V10.6 Snow Leopard :: Upgrading From 10.6.5 To Mountain Lion?

I'm running 10.6.5 on my Mid 2010 15" MBP. I was also a MobileMe user.  

Now I'm thinking about upgrading to Mountain Lion upon it's release, and have questions to help me decide if I want to use iCloud or not.  

1) I have zero interest in Lion and want to skip it, going directly to Mountain Lion. Can this be done?  

2) If I choose to use iCloud, during setup, one is given a list of checkboxes for the items they want to sync. One checkbox is labeled "documents & data".

Once this box is checked and a sycn is executed, what specific files are uploaded from my MacBook Pro?  

Do I have control over what goes up into iCloud? Initially my iCloud usage would be mostly data files, I would want to choose which files go to the cloud and which files remain on my hard drive. Is this possible?  

The amount of control over what goes into the cloud is my main concern. If I have total control, then iCloud will be great. If not then I will use another solution.

Info:
Mac OS X (10.6.5)