Epson make tens/hundreds of different PJs, you’re going to have to be more specific, we are not psychic.

Epson Home Cinema 1080 3-chip 3LCD 1080p Projector, 3400 lumens Color & White Brightness

So, no ARC port. The Roku would go in to the HDMI port (one of them), the audio out via RCA from the red and white jacks would go to the RCA input jacks on the Amp. There will be a 75ms minimum delay on the sound, you may notice a slight lipsync delay. 

And, you’re only going to get stereo out of this device, not 5.1. 

Apologies, not the white and red RCA jacks, those are inputs, not outputs. You’re going to need a 3.5mm stereo cable that goes to RCA jacks that would go to the RCA input on your Sonos Amp.

Thank you! This definitely helps. Isn’t what I was hoping for but still solves the issue.