In this instance, I agree with what news Herself received. The squealing came from one of the three serpentine belts running over a tensioning pulley. The bearing for this pulley seized, the pulley no longer moves, and hence the smoke as the belt heated up running over a non-moving surface. Bad news. This meant that Forrest NissanPickup is not up to the couple hundred mile round trip to SCA this weekend.
Good news. This happened before Herself set off down the highway.
Middle news. This particular belt drives the power steering pump, a fact implied by Herself describing the steering becoming stiff and hard while trying to make 90 degree right or left turns, but not being so bad on the road (she did drive Forrest home, slowly, with the feed). This is verified by tracing the serpentine patterns in the owners manual diagrams. It's the outermost of the three belts, identifies the power steering pump as the one operated by it, and we've also traced the power steering fluid reservoir tubing to this pump.
Our worst-case scenario is of course that there's something else lurking in the background. Forrest is, after all, 189K miles old. Middle case scenario I suppose is that all the belts & associated pulleys may need replacing. Or that along with the power steering idler pulley seizing some damage occurred to the power steering pump, requiring replacement. Best case scenario is it's only the idler pulley, and it is about time for those belts to be replaced anyway.
It is, of course, time for that latter, and the truck is due in for annual Preventive Maintenance which would include those belts. So Forrest just told us early he's ready for that.
Herself will day-trip on Sunday, the one day of the event which has critical attendance things for her. Today we will do the shopping errands we need to do, timing those to coincide with going to see Indiana Jones and the Kingdom of the Crystal Skull