Is the brown area where the green caudex meets the yellow/beige root which was beneath the recent soil level?
May not be anything to worry about , just keep any eye. Is this area similar in feel as the whole caudex?
I would tend to pot it up (already done) with this area above the new soil line as you have already taken it out of it's original pot.
Previous mix looks fairly dark. Looks like it may retain a lot of moisture?
Pot up and leave for 4-5 days before giving any water.
I have one question about root in photo.
Is the bulbous part at lowest point darker than the upper part or is it just my eyes?

Thanks for the response! To answer your questions:

- The soil came up to right below where the caudex is at it's lightest color (below where it's at its darkest color). I hope that makes sense. I've been wondering if it was supposed to be higher above the soil, as in a lot of pictures, I've seen the large bulbous part above the soil line.

-The soil I was using was a store bought Cactus Mix, but today I repotted it with that soil mixed with sand, and I also put stones at the bottom of the pot to help with drainage. I'm thinking of tracking down all of the materials needed to make a "gritty mix".

- The bulbous point does look darker than the upper part in the picture, but I think that is just due to a shadow and the dirt that is matted on it. It's general the same lighter color as right above the bulbous part.

I've attached a picture of how I repotted it....

Thank you thank you thank you!

I think the height at which you planted it is fine. This way you can watch and it is raised above soil level and exposed to air.
The gritty mix of Al's on this site is wonderful. Sand is not necessarily the best, but leave it for know, just make sure to let it dry back and do not over water through the winter.
Keep everyone posted.
Rick