you'll probably get a better answer before the day is out but here's one idea ...
finish quilting the part you like. baste the rest. zigzag around the edges, then toss it into the wash. pencil usually comes out. re-block it while it's damp, then re-mark when it's dry. (May i ever-so-gently suggest a trip to the store for an air or water soluble marker first? :wink: )