That switch will definitely do the trick, but why not get
a switch that also serves as a wireless bridge so you can do away with that unsightly 50' cable run as well?
It probably won't be plug-and-play because you'll have to configure it to access your existing wireless base station, but we're here for you.
EDIT: I just noticed that you were planning to redo the wiring so it goes through the attic. Whenever I can, I prefer to use a cable, but if you want to save yourself some attic intrusion....