You would probably want the writing on plain muslin. Buy yardage, cut into manageable pieces, iron freezer paper on back, cut squares, then use a permanent pen to draw borders 1/4" from the edge. This prevents people from writing into the seam lines. (Basting stitches will work too, but you would need to cut the pieces first, sew the basting lines, then iron freezer paper to the back -- which I think would be more work.)
You can get a couple of charm packs, but these would be used to create some kind of pattern around the "guestbook" squares.