It is a beutiful quilt. I would do an allover interlocking orange peel shaped pattern, the shape of the flower petals in the print. Since the striped sashing is so geometric the curved piecing would soften it. As for stitch in the ditch as a handquilter I never do that. I often echo the seams a 1/4 inch a way from the stitching line to stabilize the seams, especially if it is handpieced. You could do it without a hoop or frame if you basted it well and supported the parts of the quilt you were not working on with a table or other flat surface. I often take my quilts off of the frame to finish the borders. I lay the whole thing out on my ping pong table and turn it to the unfinished portions as need be.