Traceroute results correspond to whole routers, not their individual interfaces. Even though a router has multiple IP addresses on various interfaces, it will always produce only one trace reply.
When doing so, the router will usually send that reply using an address from whichever interface the original request arrived through – in this case the LAN ...
If you have windows 7 (for some reason it was the only version of windows that had proper support for it), it has a LLTD tool built in, that you can access from "full map" in network settings.
I have a question asking for it on newer versions that shows the UI. It'll even show a network device that's got no IP (intentionally or otherwise)
The router's IP IS the one of the gateway if you are within the LAN side of it.
So route -n (or ipconfig /all on Win) shows the IP as the gateway IP.
[Maybe your problem is more that you do not get an HTTP connection to the management GUI. This could have different reasons, and needs its own analysis.]