I embedded this script in version 27 of my mod, so that way if you are using my mod, all you have to do is hit the button and you are instantly connected :). You don't need to mess with having an autorun.lua or the script manager (although I really recommend you use the script manager anyway if you want scripts). Multiplayer is only partially loaded until you maximize the chat window, so it doesn't get in the way at all.
And if anyone has ever had issues with server freezes, desyncs, and infinite loops before with this script, version .6 and the recent server changes should fix almost all of that. You don't need my mod for that.
You ought to include an option to set your name (I've already modded that, it's quite easy). You could just type, say, /name (NAME), and it would set your name.