@toddcodish
To be honest, I think you don't give yourself enough credit. If I understand correctly, you're able to confirm through your router admin that there's at least one device connected via a wired LAN connection, but you just can't confirm whether that device is your printer or something else. Most users wouldn't be able to tell either (and many wouldn't have gotten even that far).
One possible approach is to compare the first half of the device's reported MAC address against the known MAC prefixes reserved for Brother Inc. Every manufacturer has an assigned "domain" of MAC addresses, which can be used to identify devices attached to a network. Below is a link to one public MAC database which you can search for "brother".
http://www.wireshark.org/tools/oui-lookup.html
Alternatively, you can try searching for the first 6 characters of your device's MAC address to see if you can determine the corresponding manufacturer. If you have a smart phone that you're able to connect to wirelessly to your router, another option is to download a free network scanner application such as "Fing" to scan your network and attempt to identify any devices it finds (the accuracy of the results can vary).
All of the above is merely to help confirm that your printer is successfully attached to the network and to determine its IP address, which is often needed to proceed with setup. Assuming you're able to successfully identify the printer and its IP, then you should be able to attempt proceeding with the driver installation and configuration. I do strongly suggest that you refer to the other links provided by Kevin, as some of the suggestions covered therein may also be applicable to your issue (e.g. resolving firewall conflicts, etc.)
Also, in the event that you determine the device connected to your router is not the printer, then you're attention will need to focus on getting the printer connected (and visible in the router client list in the admin UI). There should be some menu or controls accessible on your printer which expose network settings. You'll want to find an option for DHCP and ensure that it's enabled before restarting your printer. Other things to check are that your ethernet cable has no defects and is connected securely on both ends.