I think that is a brilliant idea. Love the backside grid.
I've tried both the easel pads and the newsprint. And even old phone books. Yep...they still print them.
But lately, I have been using water soluble stabilizer instead of paper because I was given an 18" x 25 yd roll of it. I love being able to squirt away the "foundation" and I have even remembered to use my permanent pen or wash away markers. So far, so good.
If I ever run out of the water soluble stuff, I will try your wrapping paper idea.