Summer Orientation

Can anyone give me input on how important it is to attend summer orientation? My son has been to Furman many times including 2 official visits, during which he met with many professors he will have. My husband and I attended Furman, so we are quite familiar with it as well. We live a days travel away which will make it a 4-day trip. We are certainly willing to take him, but just wondering how much of a benefit it is. Does anyone know how many attend each session? Will it make my son’s chances of getting the classes he wants/needs much more difficult waiting to schedule until Fall.