Need to use ethernet cables for other equipment but Panoramic Modem is too far away to run cables - what are my options

First question is what will you stream to your audio system?

Second, what's on the other end of the coax connected to your TV?

If you go wireless, I wouldn't position the router "near" your audio system...but in a position for best reception from the Panoramic.  Even streaming hi-rez audio at 320 Kbps shouldn't be a problem for wireless.