2006 F-150 5.4L 4x4 Lariat with 206500 miles

It has been the most reliable truck I've owned; until today.

I hadn't cranked it since Tuesday till this AM. Went to crank and it was completely dead.

Was able to jump it off. It idled great, revved normal, so I put it in gear to drive around the block.

I made it about 500 feet, then a popping noise, and then nothing. Completely dead. No PS or PB, just all systems down...

Jumped it off again. Seemed normal, put it in gear, started to give it some gas... then again, the slight popping noise, and dead.

It's on the side of the road. Need help figuring out where to start.