Glad that you can hear AA. Its a great beacon. It soothes the nerves.
I have done a lot of NDB approaches. The great thing about them during training, is you could pick some random broadcast station away from an airport and do the approach. My instructor would get NDB approaches from all over the country, including some higher altitude ones from Montana, and we would do the approach over 1310 KNOX. We weren't talking to ATC and my instructor was "ATC." It was fun and was able to do a wide variety of things without bothering anyone.
As a civilian, I never did any TACAN approaches, but we have our VOR approaches. Back then, GPS was only that which the military could use. One of our planes had LORAN-C receiver in it, but I never used that. All I could ever get it to do is display the current Lat/Long, which was kinda useless. It probably did more, but never had the chance to explore it in depth.
I did a PAR approach into an an AFB which may have been the most fun approach I've ever done. Sadly, PARs are rare these days too. I think the nearest one today that has a published PAR approach is in MO. Its on my list of things to do (again), but that's a trip.
Dual ADF with an RMI would be the best. The RMI makes NDB navigation & approaches very easy. Getting a plane is on my list of things to do and ADF in it is required. RMI would be very good. Dual ADF + RMI would be a dream come true. And if eLORAN gets going in the U.S.... that goes in the plane too.
Back then and even now, I consider the ADF the "entertainment system." Listen to music & whatnot on it. These days, people talk about the ADF & NDB with disdain, but I tell them how great it is. After my flight using MW broadcast stations for navigation... I think they think I'm nuts. But I'll work on them, starting with leaving the ADF in the aircraft and not removing it.
The list of SK NDBs in MN is rather long. I'm afraid to venture into the neighboring states. I flew up to Churchill, MB many years ago and they had a beacon up there. That was decommissioned a year or two ago. Too bad too, it was nice hearing that one. I'm still on the watch for Alert, NU on 305 kHz near the top of the world and see if it ever comes down there. So far not a peep or even a hint of a peep for that one.