I personally like pinwheels. I would do them all in pinwheels or alternate a pinwheel and a square in square instead of just a few pinwheels. I would do a narrow sashing, but not necessarily white. You have all the basics - what color does your friend prefer. Use that for a narrow sash and a narrow frame border. Then you can decide if it needs another border or just binding. As for quilting, you could STID down the diagonals in the pinwheels (another reason I would do them all as pinwheels), and then down the center of the narrow sashing. If you choose to do a wider sashing, then I would STID both sides of the sash. If you choose to add an additional border, you could do a very long zigzag down the border. These are all fairly easy to do with regular feet on your machine. No matter what you choose, they will treasure the gift!