Thanks for all the suggestions fellas. Here's what I figured out this weekend (besides the fact that 90+ degree weather everyday since March has made me want to just give up on life in general): The lower ball joint does come out from the top, towards the big hole in the knuckle. Buying a new joint and looking at it made this clear. I used an impact gun to get the joint about 2/3 of the way out and then the little cup that the directions say to use on the side your pushing out got bottomed out on the knuckle. Thing was, my little 1 hp compressor didn't have enough power to back the screw off so I could remove the adapter. Luckily the shop on the corner had some guys hanging around Saturday morning who let me use their big two stage compressor to back the screw off and take the adapter plate out. Then the ball joint came out and the new one went it with no trouble.
Now I just need to get my spindle right. The bearing looks good and still has plenty of grease, although I need to repack it. The outside of the spindle looks pretty corroded. In fact, the hub with the wheel bearing and grease seal will not fit back on the spindle. Today I will put the spindle on my 1" belt sander and see if I can get it right.