Didn't scare me off...just prompted me to go look a little closer before digging in. Thanks for the great advice and pix, though!
Turns out (knock on wood) the lower radiator hose had a pin hole. This pin hole was only noticable when the rig was at operating temperature, and the radiator full of water. Anyway, the pin hole just happened to be spewing a small stream of water right onto the serpentine belt and the alternator pulley. To make a long story short, I think the water was making the belt whine a bit....and it was affecting the alternator's ability to charge the battery.
I sprayed some belt dressing on the belt and the pulleys, the whining stopped (thank God!), tells me the water pump is likely OK for another 15k miles, then I have to decide if I'm gonna replace the water pump or have it done.
Now, I know what to expect, and for that, I am grateful to all of you!
Damon