Question: The URL <http://www.routerlogin.net/> isn't working on an internal network when I try to access it via a wireless connection. Why is that? What is the best way to configure this router to be able to access the router via a wireless connection to manage it.

Answer: 
Have you got your DNS server set as the router? If you haven't, using the routers IP address will work just as well (it's often <http://192.168.1.1> but dependant on the router)

The way this works is that the router hijacks any requests to www.routerlogin.net and redirects them to the local router. If you haven't got your DNS server set to use the router, it can't hijack the request and redirect properly.

What do you get when you visit <http://www.routerlogin.net>? When I browse to that (on my non Netgear router) it bounces me off to Netgear's support home page.
I got this error because I do not use my N300 as the primary DNS. If you temporarily change your networks settings to use the AP as your nameserver, then it is possible to connect.