It's probably worth stressing that all AC servers function as LAN servers. The -m switch is only to prevent (or change) masterserver registration. If you're running a server, anyone on the same subnet should be able to connect.
edit: ...oh, and there's a command if you want to keybind it - /lanconnect.
edit: ...oh, and there's a command if you want to keybind it - /lanconnect.