It really depends on the horse and how quickly they acclimate. Some horses don't travel/move well usually because they just havent experienced it much. Then again some horses never adjust quickly, even well trained show horses that need to arrive a day early to a show just to settle in. You said you've never boarded before so is this your first horse or a new horse? If you are not all to familiar with the horse yet, use your best judgment and when he seems relaxed, take it slow. If its a horse you know and are comfortable with, you'll know when its ok. He may be fine that same day, or it may take a few days.