I learned in a class (and I don't recall the teacher) that if you pull a color from your quilt for your border then the quilt becomes that color. It is amazing, even with all the lovely colors that you have in your quilt, the quilt will seem to be predominantly the color of your border. So, I would select one of the colors in your quilt for your border. I like the idea of a narrow brown border and then select a brighter color from your quilt for the wider outside border.