I ended up going with my idea of embroidering leaves on the blank squares of the doll quilt. I picked Oak and Maple since they're the most recognizable and interesting looking. It took a long time to do but it turned out awesome!
I did the leaves by printing out shrunken pictures of leaves and tracing them onto the fabric with a disappearing marker. I just backstitched the outlines.
Do you see where the side border pieces are a little too wide? I had a dream last night that I tried to even them up and accidentally cut off almost the whole border! That's a really weird thing to dream about, but I'm definitely going to be really careful cutting it.