I like what you have done. I did that type of quilting of lines in my quilt that I use for my avatar photo. I would not do a cross hatch the border but just do a single line. You could just extend the line into the border. Or have it go in the opposite direction at the same angle. If you cross hatched the border, it would be more heavily quilted then the quilt. I always try to balance out the stitch in both the quilt and the borders.