Fortunately, the nightshirt fit me perfectly across the shoulders, so no adjustments there. I cut off eight or so inches off the bottom and got started. First I opened up the collar seams and removed the collar, leaving just the band which I restitched. I took in the side and sleeve seams quite a bit.
On the placket, I removed all buttons and sewed the bottom two-thirds shut. Then from the fabric piece cut from the bottom, I created ruffles cut on the bias and sewed them right onto the placket. I like the current ruffle-trend but in small doses, so this worked well for me.
I used a hem facing and finished with a double-row of topstitching. With facings, I have been understitching (using Karyn's tutorial) which makes a big difference in the finished product. After cutting the sleeves to three-quarter length, I considered adding a bias cut binding, but decided to go with a simple casing for elastic.
This is an easy top to throw on for a comfy weekend day.