You can tell I'm a newbie with Android apps. I finally looked a little deeper into PowerAMP and found I browse to their website on the Kindle Fire and install it from there by simply allowing non-marketplace apps. It seems to be working just fine.

It's still not quite the ideal portable music player I want to take to work with me, but it's not bad. I bought a neoprene sleeve by BUILT for it, and an AmazonBasics stylus. I'm using a BookGem book holder to keep it in place, though it only works in landscape orientation because of where I need to plug in the audio cable. But yeah, the pair of black M3 v3s that I bought a while ago ended up at work. They're powered by an AudioSource AMP-100, so this is what I hook my music players to when I'm there. It's nice working in a storeroom during the evening shift. I get to blast my music after day shift leaves at 4:30.

I suppose the only thing the Kindle Fire needs is expandable storage to do what I want it to.