I would move if it was me. First off the fact that the stall is not being cleaned everyday is not ok. Second it's winter and you can save money by moving your horse home. If your horse is home then you can take care of her the way you see fit. That will buy you some time to find a new trainer. A lot of times you can haul in and take lessons from a trainer without the horse boarding there. The blanket issue is something that you probably have to provide yourself. I have never known a barn to provide blankets for people. It also kinda sounds like your horse needs a little bit of a better shelter with the type of weather you have. You don't have to put up with a BO like that, especially since you have horse property!
And unless your wife is planning on doing some big time showing there is no need to be drilling the horse every day, especially as young as she is.