To quilt or not to quilt an antique top. If you are looking for resale value, then do not. If you want to keep it as a heritage item, then hand quilt it with the 1/4" in the ditch. That is the traditional way to do the log cabin. For the first quilt from the SIL, carefully adjust those squares to the side as suggested, add a solid red with the wonderful fabric you also showed, It will make it a bit larger, still keep the vintage appeal, but get it to a workable size. Even if you do decide to hang it, your quilting will show and all will admire the work of the makers. As for the second, I would not enlarge it. The maker did a great job keeping it square and usable. I would definitely do the hand quilt since hand pieced but do not need a heavy batting. I would put in a light wool batting or a flannel, otherwise it could get to heavy to hang if you wanted to do that. 1/4" in the ditch stitch by hand. I have a couple of antique quilts, and I love to admire them completed. Every once in a while, I will put them on the bed to enjoy them.