I want to be one. Within reason.

I can basic land nav with an eTrek with the best of them, and am a waypointing son of a [gun]. I have been trying to expand my envelope with this Map Source and Points of Interest stuff in the context of two upcoming ops:
  • Vacation to MA, with a little Freedom Trail action thrown in
  • Generic intent to pump up the GIS component for some battlefield tours in the MD/PA/VA area. Maybe famfire it in conjunction with the Civil War Century.
I spent some time on the Garmin site and found the conceptual orientation and the FAQs to be wholly lacking for the way my brain works. The site lays out some coordinating instructions for various widgets, but not the intent. I can't see the forest for the trees. I know there's a world of stuff out there behind the green door, but right now me confused. I've heard of housewives deftly uploading all the kid-friendly items on their vacation route, but I'm still staring at a bowl of jello, a laundry list of external providers with no triage, and plenty of expensive map products that I don't know what more or less they do for me. Some of my top questions at the moment:
  • Is there a good POI service for that kind of historical Stonewall got shot here, Washington slept there stuff? And any others just for GP, as I plan to eat, drink, and be merry, too?! Free is nice, but I'm not incurably cheap so pay is fine if the value is there. BTW, I found the garmin POI loader tool and downloaded it. The mission now seems to be to hone in on the right POI provider(s). I can do the slot A into tab B stuff OK once I'm past the source selection.
  • What are some good companion desktop tools? Again, free is nice, pay for value is fine.
  • I see there are beau coup additional basemaps available. I understand the use for one in a new AO (e.g. Australia vs. North America). But when you're talking about using another one for the same AO, do they play well together? Any experience with some good ones?
  • What is all this MapSource Unlock mumbo jumbo about? I tripped across it in the context of checking for updates on the installed base map. It seems I have the latest version. But I have the key to unlock something, and I damn well want to, without pointlessly shooting my unlocking wad.
I've had an eTrek Summit (no base map, e-compass) for ages. I just got a Nuvi 660 for the car. It has the CityNavigator North America NT v8 base map -- which incidentally SUCKS at Camp Lejeune / Cherry Point since it doesn't see the new and improved 17 / 24. But otherwise is a handy piece of gear. I must master it.