Many thanks to all involved.
I’ve got Volumio working with a Behringer U-Control UCA222 DAC sending music to a Denon AVR in the living room HT system. The quality sounds good thus far.
I have not been able to connect to the primary music library that lives on an older Windows Vista box on the same network in another part of the house. I moved a few folders of music to a USB thumbdrive to test the audio quality and rocking out right now.
In the future I hope all 300GBs of music will communicate nicely with Volumio and I will be streaming the tunes to a vintage Harman Kardon 730 ‘twin’ and big Polk Audio RTA speakers (new and old coming together).