As far as the fracture, you'd have to ask your vet.
As far as the cold, I wouldn't worry. Vermont can get pretty darn cold, and we have horses at our barn who have come from all over the world, including one who lived in Florida until last year. If you are coming for school, I'm guessing the horse would be moving late summer/early fall, which would be ideal. He could settle into his new home without the drastic temperature changes.
My horse is well adapted to the cold, as he was born in Canada, but there are a few things I do to make myself feel better. I keep him bodyclipped, which, as backwards as it sounds, really helps. He works year-round, and nothing chills a horse like being wet and sweaty. Before he was clipped, it would take him 3 - 4 hours after a ride to dry off. Now, I can toss a cooler on him while I get changed and then put him back in his nice warm blankets.
I do blanket pretty heavily. I'm an over-protective mom
. I buy good quality, breathable blankets so he doesn't get sweaty and damp.
I give him as much forage as he will eat when it is cold. Horses generate heat by digesting. Tristan isn't a great hay-eater for such a big horse, so I supplement it with hay stretcher and alfalfa pellets. I also own a small water heater, and will heat up his water when it is really cold. Some horses won't drink as much in cold weather and can have problems with impaction. Watching Tristan guzzle a half-bucket of warm water before I leave the barn helps me sleep at night.
I'm sure Ranger will adjust just fine to the cold - probably more easily than you