Okay, so our edging is done, the gusset is ahead; in the meantime there's a few inches of plain knitting to fly through. After I finished joining the cuff, I brought the yarn tail forward, so it would mark the beginning of the rounds.
You could also mark this stitch with a safety pin or a locking stitch marker - anything that will help you keep track of where your rounds start and stop. Ma might have purled the last stitch of every round, a detail that almost every period stocking and sock would have had, mimicking the seam on old-fashioned sewn stockings, but also having the very practical purpose of marking the beginning of the rounds, where to place decreases for a shaped leg, and keeping track of stitch counts through the heel turn.
From here to the wrist I can just knit every stitch in every round until the cuff is long enough. I like my mittens to have a long cuff - I have long arms, and coat sleeves tend to leave several inches of my arm bare to the fierce winds of Midwestern fall and winter. I put longer cuffs on my kids' mittens too - for toddlers the extra long cuff makes it harder for them to pull them off when I'm not looking, and my boys have a frustrating tendency to start outgrowing their winter jackets right in the middle of the season, when I'm hoping to get a few more weeks of wear so that I can get their new coats when they go on clearance. A couple extra inches on the mittens lends itself to frugality - keeping rapidly-elongating wrists warm until those 1/2 OFF! signs start appearing. Four inches should be sufficient. Upon actually attempting this, it turns out that four inches is far too long. A smidge over three inches is plenty long enough, looks more balanced, and doesn't shove shirt sleeves around so much.
This would be a fine section to be knitting by firelight, after the lamps had been turned down and the girls were in bed and couldn't see that Ma was doing Santa's work.