Thanks, guys. I realize, after putting in the new battery last night and seeing the ammeter showing less than good with the lights on, that something else must be the matter. I was really surprised that the brand new, out of the box, NAPA starter failed (just a loud whine like it wasn't engaging, although when I took it out and pressed the switch in, the gear was definitely sliding back into position. ???) So, I figured it was in in either the generator or voltage regulator, which is why I was asking where to start the troubleshoot process.
That said, I charged the battery for about 45 minutes today, put it back in the truck and drove back down to NAPA (also in Farmington, about 10 miles from me), and told them I bought it in mid December and it's failed me twice. They were going to test it, but I told them I'd just charged it, so they just said they'd give me a new one. Took the other one back to Wallyworld and told them I didn't need it, got my money back. (Not exactly honest, but the Walton's will be ok, I think).
Thanks for the tips, both of you. I really appreciate the in depth list, Kenneth. It's too dark to get anywhere on it tonight (spent the day putting my heater back together and trying to drill out one of the housing to side panel bolts from it's nutsert. It's starting to get chilly around here at night, so I thought I could at least get that out of the way. Will check off this list tomorrow. Thanks again!