I finished the front, sewed the shoulders together, and picked up stitches for the first sleeve last night. I followed the instructions in The Knitter’s Handy Book of Top-Down Sweaters for working the set-in sleeve cap seamlessly from the top down.
The technique is a little fussy because you have to first pick up the right number of stitches around the armhole, then you have to follow a specific series of short-row wraps and turns until all of the stitches have been worked. Once I got started, I didn’t want to put the knitting down until I had joined for working in rounds at the base of the armhole. But it sure beats sewing a seam!