At the remote site, the RRAS server (which is also a DC) has the IP address, but my local machine also happens to have the address; but when I connect via the VPN connection it's addressed by and my computer is, so that sounds fine, but still...

Um, why does this sound fine?

You should be trying to route between what should be two 'distinct' networks. From a TCP/IP point-of-view, the network mask is used to make this distinction. So unless your using some kind of tricky netmask setup that I can't imagine, then the best I would have ever expected to get would be simple a point-to-point connection. Though if both your (local) IP Address conflicts with the RRAS server, then I'm amazed you even get that.

Simplest solution would be to change your local IP Address range. ie Use something like locally.