Kristine is great! You can "float" your top on a larger piece of backing. This works for placemats and such. You pin the backing to the take-up rail but not the batting or the quilt top. Then you do have to pin to your other rails. Hopefully your leader for the top is long enough. Then just pin the top to the backing and batting and baste or sew right near the top edge of your quilt top to hold it.
Hope this works.