What a cute quilt! I am going to tell you how I would quilt it, though I am
not an expert at this, having only been quilting 2 years, and mainly using SID.
First, I would SID. Then I would stitch from one side to the other....half way through your large focus fabric. Then I would do the same thing lengthwise.
Then I would stitch in the middle of your border, dividing it in half, like another frame. I'd use blue painter's tape as a guide line.
I have never done stipple, and barely know what that is. Maybe that is the way to go...but I can do straight lines. I will be reading what others suggest, hoping to learn more, as I always do from this site.