When I have a quilt that needs width, I tend to add a row of scrap blocks of the fabrics used in the quilt. Here's a photo of one I made for my 2nd niece................I actually added these little blocks to the whole quilt but you can add them to just the sides. On another one I'm working on I added flying geese at either end as I needed to make it longer. Had a bunch of them already made up so was able to use up the scraps.