With a quilt that has lots of straight lines to quilt on, I wouldn't worry about having continuous lines. Anywhere your stitching finishes at the edge will be secured by the binding. I would stitch down the long lines through the middle, then go across, finally working in the smaller sections. This will help prevent the fabrics or batting from shifting. It looks like you have some large areas with no planned quilting....be sure that your batting is comparable....some battings need to be stitched every 2 inches!