Using CI on the front end and CMS

[eluser]cityzen[/eluser]
I've finally tackled some of my main concerns with CI, so now i'm on to "bigger and better things". In the past I've always coded from scratch for the most part, but what confuses me about the MVC structure is how to use it to do the front end and CMS? if I want my admin to be in a location like www.mysite.com/admin, do I just restrict access to that area (is that something CI does as a primary function?). Or is that mixing apples and oranges too much? I would hope it wouldn't require two installs of CI... Is that "best practices", if not, in the MVC world, what is the common/best practice for developing a front end and admin in a framework?

I did search and found a few discussions regarding using other CMS modules with CI, but nothing exactly what I'm looking for.

- also, where do you typically install CI? Do you usually put it in your root or into a sub folder like /CI

Thanks in advance!

Mike