It took me a couple of attempts and a lot of knitting math, but I have achieved what I wanted:
Say hello to the Alcott Shawl.
It's worked from the edging up to the neck which means that all the heavy knitting and thinking happens in the cast on and first 20-some rows. Then it's knitting and decreasing until the neck.
The pattern is available for sale and download in my Ravelry store.