Well, my loophole closed. While it said you have to return to your home area every three months to keep local channels, for MLB games it gets flagged after 30 days. I actually am doing just that next week, though it might be more than a full month after that before I'm back for good.
We'll see if this ends with me just taking the MLB.TV discount or if I can mess with my settings further later this week (right now, on the free trial).