Closing Front/Home Page Content Access to Non Registered Registered

Hi there

My BuddyPress project is about to go into a closed online beta phase where I only want invited registered users to have access to the websites content. The site is of course being posted online so I'm wondering if there is a way to keep nonregistered visitors from accessing any of the content during this phase. I would however like to have the non-signed in homepage available to the public but without any of the widget content visible. I've included a mockup image so you guys can get a sense of what it is that I'm trying to do.

Also it would be nice if their wife be a way to create a single text field or display an image in that lower white section. In the same sort of way that the Facebook main page displays when you're not signed in. I could use the text area or the image to provide more information about the upcoming website launch.
Anyhow thanks in advance for any ideas and assistance you fine people can offer.

Be well