You can easily store your music files on the NAS drive (that's what I do and have done for RB6 and previous RB versions). However, I keep the library data itself on the computer (and do regular backups to the NAS drive). Otherwise, I've found there were issues.
To have remote access, you'd also need to a VPN to securely access the drive. (Not to mention decent upload speed and a good mobile connection.)
My library is all FLAC so file sizes are 50-100meg for each track. I recently had some network quality issues and found that it would take 10-15 seconds to load each track and in some cases, I'd find that the track would stop half way through and I'd need to load. Normal operation, you wouldn't know that the files weren't stored locally on the computer.