Well, first off, I love the colors and fabrics in this quilt! It's just so charming.
I like either of the two suggestions for the quilting that you have gotten, but will toss another one in the mix: why don't you just do in the ditch on the up and down rows and not bother with the side to side ones? I think that would be enough quilting, depending how big your blocks are, but they don't look 10" wide, so you should be fine.
I do my stitch in the ditch a little different from most- I go on both sides of the seam about a quarter inch from it. So you would have two parallel lines a half inch apart for each seam. It seams to be a little bit sturdier that way. It is twice as much stitching, but it's easy stitching because you have the line to follow.