I've done it this way before. I didn't notice any issues when joining the quilted/unquilted areas. I would call the quilting density I was using moderate. It wasn't quilted to death, but not lightly quilted either. A similar method I've used was the Georgia Bonesteel lap quilting method. Although she developed this for hand quilting, I used a machine. In this method, you quilt to within 1" of the edge, then join your next row with a 'normal' piecing seam, then finish quilting the previous row. This method won't work with all quilting patterns, however. I was stippling this quilt and it worked well.