would like to know the best route from toronto to orlando?

Since you asked for alternatives, how about I81 to Winchester, VA then I66 to US 17 to I95 at Fredericksburg, VA. Mts in PA are probably no steeper or longer than those in Tenn (not been in Tenn). South of Harrisburg you stay in the valley. Would get you out of he snow sooner I think. I'm equivocating because I've never driven the I75 route north of Knoxville. I wouldn't begin either route in late night. Hope this helps.