You really need to hard wire the streamer or get one with storage. The Bluesound is a very nice streamer and there is a version with storage. Just copy your music file on to the internal hard drive. If you want to an external DAC, I believe it has a digital output as well as USB.
The reason you need to hard wire and not go wireless is drop outs. If you are streaming CD quality it may not be a problem. But once you start streaming at higher bit rates it can become a problem. The other thing I would suggest is to back up that hard drive. Hard drives can fail without warning. I have had it happen.