I really don't know too much about boot shapes, but it sounds like you're racking up some shipping costs so I'm gonna offer an alternative: book a flight up north.
Think of it, you're gonna find multiple stores stocked to the rafters, and if you learn how to book flights on the websites, you'll eventually find a flight cheap enough to make it worth it. I've had to do something similar recently and it worked quite well. Locate a cheap hotel and fly out when you have a couple of days off.
It's another option.