I have been running my Core by connecting external to my current network (internet side) and have created an additional network with AP on the internal side. This is just easier for me, because I'm still installing, rebooting, etc.. etc.. and it works just fine. This does mean you will need an additional switch/AP but those are cheap. I don't even have my core running at night at this moment, because it's not fully installed yet (still ordering hardware). I also have 2 NAS devices, so 1 on each network, this way all files we need daily are still available and I have a 1.5Tb NAS to fill up on the LinuxMCE network.
You cannot reach all the media from your workstations now, that is the drawback. And the other way, you cannot reach the info on the "workstation NAS" from the linuxMCE network (well not without fiddling).
Whenever I'm satisfied with the setup, and leave the core on 24/7, I will change my network where the Core will be the main DHCP for the whole house, that way I can also reach the Media/etc.. from my workstations.
Picture says a 1,000,000 words......
This is how I have it now, and after you live on your own, or in my case I am done setting up do it as fearingsept picture