No matter what I did I could not get a stable NFS connection to Unraid. The stale file handles problem was a continuing source of issues with Plex running on Ubuntu. I just switched to SMB and it seems to be working ok. I'm having some pausing on high bandwidth content, but that might be the wireless network. I'm not sure yet. Regardless, here's my fstab now:
//192.168.169.8/DVDs /mnt/DVDs cifs guest,uid=1000,iocharset=utf8 0 0//192.168.169.8/KidDVDs /mnt/KidDVDs cifs guest,uid=1000,iocharset=utf8 0 0//192.168.169.8/Movies /mnt/Movies cifs guest,uid=1000,iocharset=utf8 0 0//192.168.169.8/TVShows /mnt/TVShows cifs guest,uid=1000,iocharset=utf8 0 0