This next step begins with transferring the provisionally cast-on shoulder stitches to a needle (I used a 24" 5.5 mm while I retained the back stitches on a 32" length). There's a link to my tutorial on doing this, and if you've never done it before, the tutorial has some useful info, especially regarding what to do with the last stitch. I also followed my own instructions to thread a short length of waste yarn through the cast-on stitches to make it easy to count the number of rows from the shoulder in order to make the fronts match the back. See?
The fronts go quickly and now I have everything joined up and the first two rows of the lower body all done.
It's clear sailing from here. I'm looking forward to the excitement of the front lace border!