Heya,
For a quick media server, you can get an nVidia shield (instead of using a proper NAS or PC on the network, which is just added complication) and install plex server on that as a super easy solution. Then just put the plex app on any device (tablet, phone, streaming box like roku, shield, smart TV, desktop too for PC has it). It's glorious for album art, playback, etc. Super easy to use. My 7 year old can get through it all and find her stuff no problem. You could have the Shield plugged into the receiver for playback and control from Plex app on her tablet.
Very best,