Andre,
Thanks for the help. I made the changes you suggested and I thought all was well. I took a 12 hour road trip with Poweramp running the whole time and had ZERO issues.
But, I have also taken my usual commute trips on a few occasions and, though the music seems to be playing randomly and from the same folder, it will still stop playing at times. It's inconsistent too as it will play fine for 4-5 songs, then stop - right in the middle of it playing - on the next 2 out of 5.
The only difference between the trips is that it quits when I'm flying. That shouldn't matter, yes?