The Nas wasn't difficult at all, nor was the Squeezebox... the only slight, and I mean slight, hurdle was configuring the router.
I think the best thing to do is set up the NAS, bung all your music on it. Key thing is to use RAidar and click on SETUP, to open up the browser page that controls the NAS. Click on Streaming services and enable the Squeezecenter. Then get Squeezecenter to scan your music files on the NAS. I use the 'experimental scanner' on the 'Streaming services' page and it works fine.
You have to direct the Squeezebox to the NAS as the music source.
I installed version 7.3.3 of Squeezecenter onto the NAS (
not the pc) and it seems to be a massive improvement over the basic version that is pre-installed on the NAS.
Available
here (obviously select Readynas duo on right hand side)
Also worth doing is ensuring that you have the latest NAS firmware(RAIDar, the browser page, and RAIDiator the NAS firmware)
here EDITED WITH NEW LINK
THIS forum is very handy, although you may already know of it.
I don't think you will find any of this a problem