Give as much advanced notice about upcoming events as you can. Perhaps research the web or order brochures before departing. Let the children investigate where they will be going prior to the trip. Take sensory breaks and have calming things with you. This is important for the adults in the vehicle too.
Teachers switch jobs.
Buildings get shuffled around. If it's a new school, investigate it early. Take some pictures of the outside of the building. Get some with your child if possible. Check out the playground.