I think that the idea of taking in the shoulders and side seams, maybe even the back seam, would be good... but this is easier said than done because I sewed the entire dress with french seams. Between that and the gathering, I wasn't going to move any seams.
|French seams, so lovely, so hard to alter.|
In the photo above, you can see the quick save I tried with snaps to overlap the front. This is the outcome, which works if I don't move at all.