I give you credit, once again, for trying to have a cordial co-parenting relationship with your ex and with the step-siblings!
In our experience, the drop-off is a half day affair. You'll have to check with the individual school, of course, (and hopefully they have sent a schedule, or will soon - but maybe it went to the student?) If not, you can request something from the school. For references, ours was like this:
- go to new student registration to get ID and room access info (key code, whatever).
- pull up at dorm and unload stuff, start hauling it to the room. Some schools have crews of upperclass students who do a lot of the hauling. If there is a high rise dorm with an elevator, plan on long delays.
- get room set up (boxes unpacked, bed made, computer set up) if the kid will allow it. Sometimes they want to do things themselves. In any case, it won't be everyone - you have a large family and there is no way you will all fit in a typical freshman room.
- greet roommate and perhaps exchange pleasantries with the other set of parents, maybe meet the RA
- go to 2 separate orientations, one for the student and one for the parents. Our parent orientation basically said, warmly and with love, "Welcome. Your job is done. Your kid is grown up. Don't call professors to get extensions, don't call the dean of students for your kid's grades, don't call the health center to find out if they've been seen or if they signed up for birth control."
- grab lunch at the dining hall or wherever they have things set up for you. Probably you will have to pay for this.
- maybe make a trip to the bookstore for supplies (mostly things with college logo on them; you'll get better prices at the local Target or Staples for room stuff). Otherwise, just put money in her account and she will pick up stuff herself when her professors tell her what she needs.
- say goodbye and go home (or sightseeing) so child can settle in.
- optional: come back after dinner for a ceremony on the quad in which the kids all formed a circle and lit candles as a sort of kick-off. They walked through a main gate as a procession, and this was actually replicated 4 years later on their graduation day. A lot of schools do something along those lines. But parents/families were in the back rows and the kids took center stage.
In my experience, the freshman doesn't want the parents hanging out. This is not Parents Weekend with activities to integrate the family to college life. College life hasn't begun yet and there's really nothing for the college kid to share with you. They're ready to have you take off and not prolong the goodbyes. After this first day, there was absolutely no provision for parents being around. New students did things like dinners in town with professors' families or other town "dignitaries", a hike to the local state park, and other group-building activities.
If it were me, I'd get a hotel nearby for the night before, then arrive in the morning. I'd take some stuff for the younger kids to do in one of the public lounges while you do some of the parent stuff in the room once the hauling of suitcases and boxes is done. Then set up the room (or in your case, have Dad do it with daughter unless she wants your touch on things). Take a mini tour if they offer it, or do it on your own. But classes won't be in session so I'm not sure there's much benefit for your or the younger kids to see empty classrooms or the gym. So I'd leave by mid-afternoon and go off on your family vacation.
Good luck!!!