DanDerhy,
I didn't quite understand the question. As Mark already answered, using the CMS with the document tree in a remote server is possible. I remember that Mark uses that kind of setup.
And managing other CMS-module sites well, I'm not sure. I can imagine two Phprojekt servers with the CMS, using one local (in the LAN) and one remote (in a WAN/Internet). But I'm not sure what would that be good for.
And managing other unrelated sites no. Even though there is a XML-RPC interface planned for version 0.7.0, it will be a server-side interface, not a client one.
If you could give us more details about what you have in mind, we can help you better.
Regards,
Mario A. Valdez-Ramirez.