Good looking quilt!
By the time you get done doing stitch in the ditch, you will tackle free motion quilting without batting an eyelash .... also!
If you are going to do a stitch in the ditch technique, be sure to get a walking foot for your sewing machine (you will thank me later <g>)
As far as a border, did you consider black?
I see that you are thinking scrappy, and that will be a good choice, also ... are you going to make the scrappy solid color? any alternating with the background fabric? probably not, now that I think about it ... how long will each of your scraps be?