I made a denim rag quilt for my sons. I backed them with heavier LQS cotton fabric and no batting. Denim quilts are very heavy and take forever to dry when washed. They do stand up to a lot of abuse which makes them good for a kid or guy quilt. I would recommend backing with lighter weight fabric and do a very simple stitching design. You have a lot of seams to sew over---make it easy on yourself.
Looks very nice in your picture.