Got the hard part of the stairs done. I'm doing them in two pieces, since even 16 foot 2x12 isn't quite long enough. The upper halves needed just over 8 foot pieces, but because of the angles I was able to cut them both from a single 16 foot. I'm going to build the bottom half as a removable piece before I pour a pad.
I've got the open stringer done, but really needed the top and bottom stairs in place before I could line it up. The biggest problem I have is finding common reference points to measure from. I used the open stringer to mark the closed stringers before I put them up, but I miscalculated something--Apparently I didn't account for the height of the decking, so the stop step was going to be an inch shorter than the rest. I wound up installing the top step where it really belongs, then using the open stringer to mark the bottom step of this set--That way the open stringer will fit, and I can use it to lay out the rest of the steps.
My son came to help a bit--While I was trying to figure out what I was going to do next, he was horsing around with the footer hole I'd started and abandoned when I hit what appeared to be a solid layer of brick. He got past the bricks where I'd stopped, and it looks like it is just dirt the rest of the way down--I'd expected the same sort of rock piles I'd found in a couple of the other footers. That will let me move the corner post of the landing to where I wanted it in the first place, greatly simplifying the required bracing.
These stairs are as narrow and steep as code allows. They are wider and not as steep as the main stairs to the upper apartment.