Dale_K , you strongly recommended that I get back to a two NIC configuration....is this the same as using LinuxMCE as intended (setting up a core and then having a separate MD player tied to the core)?
You don't have to use a separate MD, the Core can be your MD. The important thing is that you have two NICs in the core to establish separate internal and external network interfaces. This will make sure that all the network features (DHCP, DNS, etc.) work as smoothly as possible and makes troubleshooting much easier.