Thanks for all of the info. I did reverse the castle nut and thread back on from the start to protect the end of the axle. Never got it to pop loose. The very sturdy puller suggested above finally started to bend, so I am crying "uncle". Rather than take a chance on damaging anything on this sentimental and in very good shape car, I found a shop not 15 minutes up the road that specializes in classic autos and trucks. Everything from general maintenance to frame-off restorations. They're picking it up in 2 days. Will also give it a once-over to see if anything else needs addressing from years of sitting. I'll update with how it all went.