Does the dash go completely dead like the ignition switch was shut off? When it cut out today, did it just stumble but stay running or did you have to restart it. Did the speedometer drop to zero when this happened? Is anything else, like the radio or gauges, affected when this happens? basically looking to determine if it's a power supply issue or an engine management issue. I'd look at the fuse boxes for loose connections & corrosion, look at the engine main relay, battery connections. Does this truck have a battery cut off switch? if so, temporarily bypass it. What about aftermarket electrical accessories? I'd carefully inspect any added wiring, especially anything connected to a green wire (ignition power).
You might also look at the crank position sensor. Without a CPS sensor signal, the ECU won't fire the injectors or the ignition system. It would be helpful to be able to check for spark/fuel when it is acting up.