I think a pieced border would work better than adding just a plain border. The entire quilt is made of strips, adding a pieced border would add a little interest to the quilt.
A checkerboard border is always cute on crib quilts.
Use a tan fabric to match your blocks and a baby print that has blue/green/pink. Theres already a lot of solid fabrics in the quilt.
I think it needs a cute little print to add some interest.