I think a dark color--one of the Browns, Blacks would be good--use a figure or tone-on-tone. I learned at a workshop our guild had that the last border needs to be anything but White. I learned that our eye keeps looking for "more," and the dark color will tell the eye that it is done looking.
It has worked for me!
I love your quilt; esp. the houses on the border. You will like it even more once it is done.
Mariah