i would choose one color for a strip the same width as her strips and then a wider border for the outside...to me...i would do both in solids, because as you said, it is really busy and and the solids would calm everything down a bit and give a real canvas for some of the quilting sts to show... try to stick to her tones, they appear to be clear, crayon colors, bordering on the bright... the darker the border is, the more of a 'frame' it will appear to be, but 'dark' is relative...i would do 'her' darkest...the inner border in the same width would serve as the 'unifier,' blending her size strip with the wider border.