:hunf: Hate to be the stickler here, but I would quilt it with the walking foot diagonally, through the blocks corner to corner. The colors of the quilt are vibrant enough that the quilting will help them pop and be allot easier to manage. And I wouldn't do too much quilting if it's going to be a quilt for a child. You want it puffy and soft, so maybe only every six inches.
Good luck! Love your quilt!
Marian